<?xml version="1.0" encoding="utf-8"?>
<!--XBRL document created with Toppan Merrill Bridge  11.2.0.5 -->
<!--Based on XBRL 2.1-->
<!--Created on: 3/30/2026 3:00:06 PM-->
<!--Modified on: 3/30/2026 3:00:06 PM-->
<link:linkbase xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrli="http://www.xbrl.org/2003/instance">
  <link:roleRef xlink:type="simple" xlink:href="fkys-20251231.xsd#StatementConsolidatedBalanceSheets" roleURI="http://www.firstkeystonecorporation.com/role/StatementConsolidatedBalanceSheets" />
  <link:roleRef xlink:type="simple" xlink:href="fkys-20251231.xsd#StatementConsolidatedStatementsOfIncome" roleURI="http://www.firstkeystonecorporation.com/role/StatementConsolidatedStatementsOfIncome" />
  <link:roleRef xlink:type="simple" xlink:href="fkys-20251231.xsd#StatementConsolidatedStatementsOfComprehensiveIncome" roleURI="http://www.firstkeystonecorporation.com/role/StatementConsolidatedStatementsOfComprehensiveIncome" />
  <link:roleRef xlink:type="simple" xlink:href="fkys-20251231.xsd#StatementConsolidatedStatementsOfCashFlows" roleURI="http://www.firstkeystonecorporation.com/role/StatementConsolidatedStatementsOfCashFlows" />
  <link:roleRef xlink:type="simple" xlink:href="fkys-20251231.xsd#DisclosureSecuritiesAmortizedCostRelatedEstimatedFairValueAndUnrealizedGainsAndLossesDetails" roleURI="http://www.firstkeystonecorporation.com/role/DisclosureSecuritiesAmortizedCostRelatedEstimatedFairValueAndUnrealizedGainsAndLossesDetails" />
  <link:roleRef xlink:type="simple" xlink:href="fkys-20251231.xsd#DisclosureSecuritiesAgingOfAmortizedCostAndEstimatedFairValueOfDebtSecuritiesDetails" roleURI="http://www.firstkeystonecorporation.com/role/DisclosureSecuritiesAgingOfAmortizedCostAndEstimatedFairValueOfDebtSecuritiesDetails" />
  <link:roleRef xlink:type="simple" xlink:href="fkys-20251231.xsd#DisclosureSecuritiesContinuousUnrealizedLossPositionDetails" roleURI="http://www.firstkeystonecorporation.com/role/DisclosureSecuritiesContinuousUnrealizedLossPositionDetails" />
  <link:roleRef xlink:type="simple" xlink:href="fkys-20251231.xsd#DisclosureSecuritiesUnrealizedAndRealizedGainsLossesDetails" roleURI="http://www.firstkeystonecorporation.com/role/DisclosureSecuritiesUnrealizedAndRealizedGainsLossesDetails" />
  <link:roleRef xlink:type="simple" xlink:href="fkys-20251231.xsd#DisclosureLoansAndAllowanceForCreditLossesOutstandingLoanBalancesByLoanClassPriorToAllocationOfNetDeferredFeesAndCostsDetails" roleURI="http://www.firstkeystonecorporation.com/role/DisclosureLoansAndAllowanceForCreditLossesOutstandingLoanBalancesByLoanClassPriorToAllocationOfNetDeferredFeesAndCostsDetails" />
  <link:roleRef xlink:type="simple" xlink:href="fkys-20251231.xsd#DisclosureLoansAndAllowanceForCreditLossesClassesOfLoanPortfolioSummarizedByRiskRatingAndYearOfOriginationAndYearToDateGrossChargeOffsDetails" roleURI="http://www.firstkeystonecorporation.com/role/DisclosureLoansAndAllowanceForCreditLossesClassesOfLoanPortfolioSummarizedByRiskRatingAndYearOfOriginationAndYearToDateGrossChargeOffsDetails" />
  <link:roleRef xlink:type="simple" xlink:href="fkys-20251231.xsd#DisclosureLoansAndAllowanceForCreditLossesNonPerformingAssetsDetails" roleURI="http://www.firstkeystonecorporation.com/role/DisclosureLoansAndAllowanceForCreditLossesNonPerformingAssetsDetails" />
  <link:roleRef xlink:type="simple" xlink:href="fkys-20251231.xsd#DisclosurePremisesAndEquipmentNetDetails" roleURI="http://www.firstkeystonecorporation.com/role/DisclosurePremisesAndEquipmentNetDetails" />
  <link:roleRef xlink:type="simple" xlink:href="fkys-20251231.xsd#DisclosureDepositsDetails" roleURI="http://www.firstkeystonecorporation.com/role/DisclosureDepositsDetails" />
  <link:roleRef xlink:type="simple" xlink:href="fkys-20251231.xsd#DisclosureDepositsMaturitiesOfTimeDepositsDetails" roleURI="http://www.firstkeystonecorporation.com/role/DisclosureDepositsMaturitiesOfTimeDepositsDetails" />
  <link:roleRef xlink:type="simple" xlink:href="fkys-20251231.xsd#DisclosureDepositsSummaryOfClassificationAndRemainingMaturitiesOfTimeDepositsDetails" roleURI="http://www.firstkeystonecorporation.com/role/DisclosureDepositsSummaryOfClassificationAndRemainingMaturitiesOfTimeDepositsDetails" />
  <link:roleRef xlink:type="simple" xlink:href="fkys-20251231.xsd#DisclosureShortTermBorrowingsRepurchaseAgreementsDetails" roleURI="http://www.firstkeystonecorporation.com/role/DisclosureShortTermBorrowingsRepurchaseAgreementsDetails" />
  <link:roleRef xlink:type="simple" xlink:href="fkys-20251231.xsd#DisclosureCommitmentsAndContingenciesMaturityAnalysisOfOperatingLeaseLiabilitiesCalc2Details" roleURI="http://www.firstkeystonecorporation.com/role/DisclosureCommitmentsAndContingenciesMaturityAnalysisOfOperatingLeaseLiabilitiesCalc2Details" />
  <link:roleRef xlink:type="simple" xlink:href="fkys-20251231.xsd#DisclosureIncomeTaxesIncomeTaxesPaidDetails" roleURI="http://www.firstkeystonecorporation.com/role/DisclosureIncomeTaxesIncomeTaxesPaidDetails" />
  <link:roleRef xlink:type="simple" xlink:href="fkys-20251231.xsd#DisclosureIncomeTaxesSummaryOfCurrentAndDeferredComponentsDetails" roleURI="http://www.firstkeystonecorporation.com/role/DisclosureIncomeTaxesSummaryOfCurrentAndDeferredComponentsDetails" />
  <link:roleRef xlink:type="simple" xlink:href="fkys-20251231.xsd#DisclosureIncomeTaxesSummaryOfReconciliationBetweenIncomeTaxBenefitExpenseAndAmountOfIncomeTaxesDetails" roleURI="http://www.firstkeystonecorporation.com/role/DisclosureIncomeTaxesSummaryOfReconciliationBetweenIncomeTaxBenefitExpenseAndAmountOfIncomeTaxesDetails" />
  <link:roleRef xlink:type="simple" xlink:href="fkys-20251231.xsd#DisclosureIncomeTaxesSummaryOfComponentsOfNetDeferredTaxAssetAndLiabilitiesDetails" roleURI="http://www.firstkeystonecorporation.com/role/DisclosureIncomeTaxesSummaryOfComponentsOfNetDeferredTaxAssetAndLiabilitiesDetails" />
  <link:roleRef xlink:type="simple" xlink:href="fkys-20251231.xsd#DisclosureCommitmentsAndContingenciesMaturityAnalysisOfOperatingAndFinanceLeaseLiabilitiesDetails" roleURI="http://www.firstkeystonecorporation.com/role/DisclosureCommitmentsAndContingenciesMaturityAnalysisOfOperatingAndFinanceLeaseLiabilitiesDetails" />
  <link:roleRef xlink:type="simple" xlink:href="fkys-20251231.xsd#DisclosureDerivativeInstrumentsAndHedgingActivitiesMasterNettingArrangementsDetails" roleURI="http://www.firstkeystonecorporation.com/role/DisclosureDerivativeInstrumentsAndHedgingActivitiesMasterNettingArrangementsDetails" />
  <link:roleRef xlink:type="simple" xlink:href="fkys-20251231.xsd#DisclosureFairValueMeasurementsDetails" roleURI="http://www.firstkeystonecorporation.com/role/DisclosureFairValueMeasurementsDetails" />
  <link:roleRef xlink:type="simple" xlink:href="fkys-20251231.xsd#DisclosureParentCompanyFinancialInformationBalanceSheetsDetails" roleURI="http://www.firstkeystonecorporation.com/role/DisclosureParentCompanyFinancialInformationBalanceSheetsDetails" />
  <link:roleRef xlink:type="simple" xlink:href="fkys-20251231.xsd#DisclosureParentCompanyFinancialInformationStatementsOfIncomeLossDetails" roleURI="http://www.firstkeystonecorporation.com/role/DisclosureParentCompanyFinancialInformationStatementsOfIncomeLossDetails" />
  <link:roleRef xlink:type="simple" xlink:href="fkys-20251231.xsd#DisclosureParentCompanyFinancialInformationStatementsOfCashFlowsDetails" roleURI="http://www.firstkeystonecorporation.com/role/DisclosureParentCompanyFinancialInformationStatementsOfCashFlowsDetails" />
  <link:arcroleRef arcroleURI="https://xbrl.org/2023/arcrole/summation-item" xlink:type="simple" xlink:href="https://www.xbrl.org/2023/calculation-1.1.xsd#summation-item" />
  <link:calculationLink xlink:role="http://www.firstkeystonecorporation.com/role/StatementConsolidatedBalanceSheets" xlink:type="extended" xlink:title="995200100 - Statement - CONSOLIDATED BALANCE SHEETS">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Assets" xlink:label="Assets" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="Assets" xlink:to="us-gaap_CashAndCashEquivalentsAtCarryingValue_639104796030467528" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndDueFromBanks" xlink:label="us-gaap_CashAndDueFromBanks_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_CashAndCashEquivalentsAtCarryingValue_639104796030467528" xlink:to="us-gaap_CashAndDueFromBanks_639104796030467528" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestBearingDepositsInBanks" xlink:label="us-gaap_InterestBearingDepositsInBanks_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_CashAndCashEquivalentsAtCarryingValue_639104796030467528" xlink:to="us-gaap_InterestBearingDepositsInBanks_639104796030467528" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="Assets" xlink:to="us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_639104796030467528" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquitySecuritiesFvNi" xlink:label="us-gaap_EquitySecuritiesFvNi_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="Assets" xlink:to="us-gaap_EquitySecuritiesFvNi_639104796030467528" order="3" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="fkys-20251231.xsd#fkys_RestrictedInvestmentInCorrespondentBankStock" xlink:label="fkys_RestrictedInvestmentInCorrespondentBankStock_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="Assets" xlink:to="fkys_RestrictedInvestmentInCorrespondentBankStock_639104796030467528" order="4" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss" xlink:label="us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="Assets" xlink:to="us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss_639104796030467528" order="5" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LoansReceivableHeldForSaleAmount" xlink:label="us-gaap_LoansReceivableHeldForSaleAmount_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss_639104796030467528" xlink:to="us-gaap_LoansReceivableHeldForSaleAmount_639104796030467528" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest" xlink:label="us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss_639104796030467528" xlink:to="us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_639104796030467528" order="2" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="fkys-20251231.xsd#fkys_LoansAndLeasesReceivableHeldForInvestmentNetOfDeferredIncome" xlink:label="fkys_LoansAndLeasesReceivableHeldForInvestmentNetOfDeferredIncome_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss_639104796030467528" xlink:to="fkys_LoansAndLeasesReceivableHeldForInvestmentNetOfDeferredIncome_639104796030467528" order="3" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization" xlink:label="us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="Assets" xlink:to="us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization_639104796030467528" order="6" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseRightOfUseAsset" xlink:label="us-gaap_OperatingLeaseRightOfUseAsset_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="Assets" xlink:to="us-gaap_OperatingLeaseRightOfUseAsset_639104796030467528" order="7" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestReceivable" xlink:label="us-gaap_InterestReceivable_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="Assets" xlink:to="us-gaap_InterestReceivable_639104796030467528" order="8" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashSurrenderValueOfLifeInsurance" xlink:label="us-gaap_CashSurrenderValueOfLifeInsurance_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="Assets" xlink:to="us-gaap_CashSurrenderValueOfLifeInsurance_639104796030467528" order="9" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:label="us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="Assets" xlink:to="us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_639104796030467528" order="10" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredIncomeTaxAssetsNet" xlink:label="us-gaap_DeferredIncomeTaxAssetsNet_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="Assets" xlink:to="us-gaap_DeferredIncomeTaxAssetsNet_639104796030467528" order="11" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAssets" xlink:label="us-gaap_OtherAssets_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="Assets" xlink:to="us-gaap_OtherAssets_639104796030467528" order="12" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="LiabilitiesAndStockholdersEquity" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Liabilities" xlink:label="us-gaap_Liabilities_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="LiabilitiesAndStockholdersEquity" xlink:to="us-gaap_Liabilities_639104796030467528" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Deposits" xlink:label="us-gaap_Deposits_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_Liabilities_639104796030467528" xlink:to="us-gaap_Deposits_639104796030467528" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NoninterestBearingDepositLiabilitiesDomestic" xlink:label="us-gaap_NoninterestBearingDepositLiabilitiesDomestic_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_Deposits_639104796030467528" xlink:to="us-gaap_NoninterestBearingDepositLiabilitiesDomestic_639104796030467528" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestBearingDepositLiabilities" xlink:label="us-gaap_InterestBearingDepositLiabilities_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_Deposits_639104796030467528" xlink:to="us-gaap_InterestBearingDepositLiabilities_639104796030467528" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShortTermBorrowings" xlink:label="us-gaap_ShortTermBorrowings_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_Liabilities_639104796030467528" xlink:to="us-gaap_ShortTermBorrowings_639104796030467528" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankAmountOfAdvancesByBranch" xlink:label="us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankAmountOfAdvancesByBranch_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_Liabilities_639104796030467528" xlink:to="us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankAmountOfAdvancesByBranch_639104796030467528" order="3" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubordinatedDebt" xlink:label="us-gaap_SubordinatedDebt_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_Liabilities_639104796030467528" xlink:to="us-gaap_SubordinatedDebt_639104796030467528" order="4" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseLiability" xlink:label="us-gaap_OperatingLeaseLiability_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_Liabilities_639104796030467528" xlink:to="us-gaap_OperatingLeaseLiability_639104796030467528" order="5" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccruedLiabilitiesCurrentAndNoncurrent" xlink:label="us-gaap_AccruedLiabilitiesCurrentAndNoncurrent_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_Liabilities_639104796030467528" xlink:to="us-gaap_AccruedLiabilitiesCurrentAndNoncurrent_639104796030467528" order="6" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherLiabilities" xlink:label="us-gaap_OtherLiabilities_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_Liabilities_639104796030467528" xlink:to="us-gaap_OtherLiabilities_639104796030467528" order="7" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquity" xlink:label="us-gaap_StockholdersEquity_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="LiabilitiesAndStockholdersEquity" xlink:to="us-gaap_StockholdersEquity_639104796030467528" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PreferredStockValue" xlink:label="us-gaap_PreferredStockValue_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity_639104796030467528" xlink:to="us-gaap_PreferredStockValue_639104796030467528" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockValue" xlink:label="us-gaap_CommonStockValue_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity_639104796030467528" xlink:to="us-gaap_CommonStockValue_639104796030467528" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdditionalPaidInCapitalCommonStock" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity_639104796030467528" xlink:to="us-gaap_AdditionalPaidInCapitalCommonStock_639104796030467528" order="3" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity_639104796030467528" xlink:to="us-gaap_RetainedEarningsAccumulatedDeficit_639104796030467528" order="4" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity_639104796030467528" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_639104796030467528" order="5" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TreasuryStockValue" xlink:label="us-gaap_TreasuryStockValue_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity_639104796030467528" xlink:to="us-gaap_TreasuryStockValue_639104796030467528" order="6" use="optional" weight="-1" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.firstkeystonecorporation.com/role/StatementConsolidatedStatementsOfIncome" xlink:type="extended" xlink:title="995200200 - Statement - CONSOLIDATED STATEMENTS OF INCOME">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss" xlink:label="NetIncomeLoss" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="NetIncomeLoss" xlink:to="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_639104796030467528" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss" xlink:label="us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_639104796030467528" xlink:to="us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss_639104796030467528" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestIncomeExpenseNet" xlink:label="us-gaap_InterestIncomeExpenseNet_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss_639104796030467528" xlink:to="us-gaap_InterestIncomeExpenseNet_639104796030467528" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestAndDividendIncomeOperating" xlink:label="us-gaap_InterestAndDividendIncomeOperating_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_InterestIncomeExpenseNet_639104796030467528" xlink:to="us-gaap_InterestAndDividendIncomeOperating_639104796030467528" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestAndFeeIncomeLoansAndLeases" xlink:label="us-gaap_InterestAndFeeIncomeLoansAndLeases_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_InterestAndDividendIncomeOperating_639104796030467528" xlink:to="us-gaap_InterestAndFeeIncomeLoansAndLeases_639104796030467528" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestIncomeSecuritiesTaxable" xlink:label="us-gaap_InterestIncomeSecuritiesTaxable_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_InterestAndDividendIncomeOperating_639104796030467528" xlink:to="us-gaap_InterestIncomeSecuritiesTaxable_639104796030467528" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestIncomeSecuritiesTaxExempt" xlink:label="us-gaap_InterestIncomeSecuritiesTaxExempt_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_InterestAndDividendIncomeOperating_639104796030467528" xlink:to="us-gaap_InterestIncomeSecuritiesTaxExempt_639104796030467528" order="3" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DividendIncomeOperating" xlink:label="us-gaap_DividendIncomeOperating_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_InterestAndDividendIncomeOperating_639104796030467528" xlink:to="us-gaap_DividendIncomeOperating_639104796030467528" order="4" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherInterestAndDividendIncome" xlink:label="us-gaap_OtherInterestAndDividendIncome_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_InterestAndDividendIncomeOperating_639104796030467528" xlink:to="us-gaap_OtherInterestAndDividendIncome_639104796030467528" order="5" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestIncomeDepositsWithFinancialInstitutions" xlink:label="us-gaap_InterestIncomeDepositsWithFinancialInstitutions_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_InterestAndDividendIncomeOperating_639104796030467528" xlink:to="us-gaap_InterestIncomeDepositsWithFinancialInstitutions_639104796030467528" order="6" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestExpenseOperating" xlink:label="us-gaap_InterestExpenseOperating_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_InterestIncomeExpenseNet_639104796030467528" xlink:to="us-gaap_InterestExpenseOperating_639104796030467528" order="2" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestExpenseDeposits" xlink:label="us-gaap_InterestExpenseDeposits_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_InterestExpenseOperating_639104796030467528" xlink:to="us-gaap_InterestExpenseDeposits_639104796030467528" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestExpenseShortTermBorrowings" xlink:label="us-gaap_InterestExpenseShortTermBorrowings_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_InterestExpenseOperating_639104796030467528" xlink:to="us-gaap_InterestExpenseShortTermBorrowings_639104796030467528" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestExpenseOtherLongTermDebt" xlink:label="us-gaap_InterestExpenseOtherLongTermDebt_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_InterestExpenseOperating_639104796030467528" xlink:to="us-gaap_InterestExpenseOtherLongTermDebt_639104796030467528" order="3" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestExpenseSubordinatedNotesAndDebentures" xlink:label="us-gaap_InterestExpenseSubordinatedNotesAndDebentures_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_InterestExpenseOperating_639104796030467528" xlink:to="us-gaap_InterestExpenseSubordinatedNotesAndDebentures_639104796030467528" order="4" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal" xlink:label="us-gaap_FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss_639104796030467528" xlink:to="us-gaap_FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal_639104796030467528" order="2" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NoninterestIncome" xlink:label="us-gaap_NoninterestIncome_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_639104796030467528" xlink:to="us-gaap_NoninterestIncome_639104796030467528" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BankOwnedLifeInsuranceIncome" xlink:label="us-gaap_BankOwnedLifeInsuranceIncome_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NoninterestIncome_639104796030467528" xlink:to="us-gaap_BankOwnedLifeInsuranceIncome_639104796030467528" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainLossOnSalesOfLoansNet" xlink:label="us-gaap_GainLossOnSalesOfLoansNet_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NoninterestIncome_639104796030467528" xlink:to="us-gaap_GainLossOnSalesOfLoansNet_639104796030467528" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtAndEquitySecuritiesGainLoss" xlink:label="us-gaap_DebtAndEquitySecuritiesGainLoss_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NoninterestIncome_639104796030467528" xlink:to="us-gaap_DebtAndEquitySecuritiesGainLoss_639104796030467528" order="3" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="fkys-20251231.xsd#fkys_GainFromLifeInsuranceProceeds" xlink:label="fkys_GainFromLifeInsuranceProceeds_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NoninterestIncome_639104796030467528" xlink:to="fkys_GainFromLifeInsuranceProceeds_639104796030467528" order="4" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NoninterestIncomeOtherOperatingIncome" xlink:label="us-gaap_NoninterestIncomeOtherOperatingIncome_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NoninterestIncome_639104796030467528" xlink:to="us-gaap_NoninterestIncomeOtherOperatingIncome_639104796030467528" order="5" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NoninterestIncome_639104796030467528" xlink:to="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_639104796030467528" order="6" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="fkys-20251231.xsd#fkys_ATMFeesAndDebitCardIncome" xlink:label="fkys_ATMFeesAndDebitCardIncome_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NoninterestIncome_639104796030467528" xlink:to="fkys_ATMFeesAndDebitCardIncome_639104796030467528" order="7" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NoninterestExpense" xlink:label="us-gaap_NoninterestExpense_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_639104796030467528" xlink:to="us-gaap_NoninterestExpense_639104796030467528" order="3" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LaborAndRelatedExpense" xlink:label="us-gaap_LaborAndRelatedExpense_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NoninterestExpense_639104796030467528" xlink:to="us-gaap_LaborAndRelatedExpense_639104796030467528" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OccupancyNet" xlink:label="us-gaap_OccupancyNet_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NoninterestExpense_639104796030467528" xlink:to="us-gaap_OccupancyNet_639104796030467528" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquipmentExpense" xlink:label="us-gaap_EquipmentExpense_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NoninterestExpense_639104796030467528" xlink:to="us-gaap_EquipmentExpense_639104796030467528" order="3" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="fkys-20251231.xsd#fkys_ComputerExpense" xlink:label="fkys_ComputerExpense_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NoninterestExpense_639104796030467528" xlink:to="fkys_ComputerExpense_639104796030467528" order="4" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProfessionalFees" xlink:label="us-gaap_ProfessionalFees_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NoninterestExpense_639104796030467528" xlink:to="us-gaap_ProfessionalFees_639104796030467528" order="5" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TaxesOther" xlink:label="us-gaap_TaxesOther_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NoninterestExpense_639104796030467528" xlink:to="us-gaap_TaxesOther_639104796030467528" order="6" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="fkys-20251231.xsd#fkys_FederalDepositInsuranceCorporationPremiumExpenseIncome" xlink:label="fkys_FederalDepositInsuranceCorporationPremiumExpenseIncome_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NoninterestExpense_639104796030467528" xlink:to="fkys_FederalDepositInsuranceCorporationPremiumExpenseIncome_639104796030467528" order="7" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="fkys-20251231.xsd#fkys_AutomaticTellerMachineCardAndProcessingExpense" xlink:label="fkys_AutomaticTellerMachineCardAndProcessingExpense_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NoninterestExpense_639104796030467528" xlink:to="fkys_AutomaticTellerMachineCardAndProcessingExpense_639104796030467528" order="8" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InformationTechnologyAndDataProcessing" xlink:label="us-gaap_InformationTechnologyAndDataProcessing_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NoninterestExpense_639104796030467528" xlink:to="us-gaap_InformationTechnologyAndDataProcessing_639104796030467528" order="9" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdvertisingExpense" xlink:label="us-gaap_AdvertisingExpense_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NoninterestExpense_639104796030467528" xlink:to="us-gaap_AdvertisingExpense_639104796030467528" order="10" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillImpairmentLoss" xlink:label="us-gaap_GoodwillImpairmentLoss_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NoninterestExpense_639104796030467528" xlink:to="us-gaap_GoodwillImpairmentLoss_639104796030467528" order="11" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherNoninterestExpense" xlink:label="us-gaap_OtherNoninterestExpense_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NoninterestExpense_639104796030467528" xlink:to="us-gaap_OtherNoninterestExpense_639104796030467528" order="12" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="us-gaap_IncomeTaxExpenseBenefit_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="NetIncomeLoss" xlink:to="us-gaap_IncomeTaxExpenseBenefit_639104796030467528" order="2" use="optional" weight="-1" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.firstkeystonecorporation.com/role/StatementConsolidatedStatementsOfComprehensiveIncome" xlink:type="extended" xlink:title="995200300 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:label="ComprehensiveIncomeNetOfTax" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss" xlink:label="us-gaap_NetIncomeLoss_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="ComprehensiveIncomeNetOfTax" xlink:to="us-gaap_NetIncomeLoss_639104796030467528" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="ComprehensiveIncomeNetOfTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_639104796030467528" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_639104796030467528" xlink:to="us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_639104796030467528" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseAfterAdjustmentsAndTaxParent" xlink:label="us-gaap_OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseAfterAdjustmentsAndTaxParent_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_639104796030467528" xlink:to="us-gaap_OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseAfterAdjustmentsAndTaxParent_639104796030467528" order="2" use="optional" weight="1" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.firstkeystonecorporation.com/role/StatementConsolidatedStatementsOfCashFlows" xlink:type="extended" xlink:title="995200500 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:label="CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivities_639104796030467528" order="1" use="optional" weight="1" priority="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProvisionForLoanLossesExpensed" xlink:label="us-gaap_ProvisionForLoanLossesExpensed_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities_639104796030467528" xlink:to="us-gaap_ProvisionForLoanLossesExpensed_639104796030467528" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="fkys-20251231.xsd#fkys_ProvisionCreditForCreditLossesOnUnfundedCommitments" xlink:label="fkys_ProvisionCreditForCreditLossesOnUnfundedCommitments_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities_639104796030467528" xlink:to="fkys_ProvisionCreditForCreditLossesOnUnfundedCommitments_639104796030467528" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillImpairmentLoss" xlink:label="us-gaap_GoodwillImpairmentLoss_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities_639104796030467528" xlink:to="us-gaap_GoodwillImpairmentLoss_639104796030467528" order="3" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DepreciationAndAmortization" xlink:label="us-gaap_DepreciationAndAmortization_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities_639104796030467528" xlink:to="us-gaap_DepreciationAndAmortization_639104796030467528" order="4" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InvestmentIncomeNetAmortizationOfDiscountAndPremium" xlink:label="us-gaap_InvestmentIncomeNetAmortizationOfDiscountAndPremium_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities_639104796030467528" xlink:to="us-gaap_InvestmentIncomeNetAmortizationOfDiscountAndPremium_639104796030467528" order="5" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainLossOnSaleOfMortgageLoans" xlink:label="us-gaap_GainLossOnSaleOfMortgageLoans_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities_639104796030467528" xlink:to="us-gaap_GainLossOnSaleOfMortgageLoans_639104796030467528" order="6" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromSaleOfMortgageLoansHeldForSale" xlink:label="us-gaap_ProceedsFromSaleOfMortgageLoansHeldForSale_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities_639104796030467528" xlink:to="us-gaap_ProceedsFromSaleOfMortgageLoansHeldForSale_639104796030467528" order="7" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsForOriginationOfMortgageLoansHeldForSale" xlink:label="us-gaap_PaymentsForOriginationOfMortgageLoansHeldForSale_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities_639104796030467528" xlink:to="us-gaap_PaymentsForOriginationOfMortgageLoansHeldForSale_639104796030467528" order="8" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MarketableSecuritiesRealizedGainLossExcludingOtherThanTemporaryImpairments" xlink:label="us-gaap_MarketableSecuritiesRealizedGainLossExcludingOtherThanTemporaryImpairments_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities_639104796030467528" xlink:to="us-gaap_MarketableSecuritiesRealizedGainLossExcludingOtherThanTemporaryImpairments_639104796030467528" order="9" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInAccruedInterestReceivableNet" xlink:label="us-gaap_IncreaseDecreaseInAccruedInterestReceivableNet_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities_639104796030467528" xlink:to="us-gaap_IncreaseDecreaseInAccruedInterestReceivableNet_639104796030467528" order="10" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BankOwnedLifeInsuranceIncome" xlink:label="us-gaap_BankOwnedLifeInsuranceIncome_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities_639104796030467528" xlink:to="us-gaap_BankOwnedLifeInsuranceIncome_639104796030467528" order="11" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="fkys-20251231.xsd#fkys_ProceedsFromLifeInsurancePolicyGain" xlink:label="fkys_ProceedsFromLifeInsurancePolicyGain_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities_639104796030467528" xlink:to="fkys_ProceedsFromLifeInsurancePolicyGain_639104796030467528" order="12" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInOtherOperatingAssets" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingAssets_639104796030467528" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities_639104796030467528" xlink:to="us-gaap_IncreaseDecreaseInOtherOperatingAssets_639104796030467528" order="13" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="fkys-20251231.xsd#fkys_AmortizationOfInvestmentsInLimitedPartnerships" xlink:label="fkys_AmortizationOfInvestmentsInLimitedPartnerships_639104796030675028" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities_639104796030467528" xlink:to="fkys_AmortizationOfInvestmentsInLimitedPartnerships_639104796030675028" order="14" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:label="us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities_639104796030467528" xlink:to="us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_639104796030676343" order="15" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInOtherOperatingLiabilities" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities_639104796030467528" xlink:to="us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_639104796030676343" order="16" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:label="us-gaap_DeferredIncomeTaxExpenseBenefit_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities_639104796030467528" xlink:to="us-gaap_DeferredIncomeTaxExpenseBenefit_639104796030676343" order="17" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProfitLoss" xlink:label="us-gaap_ProfitLoss_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities_639104796030467528" xlink:to="us-gaap_ProfitLoss_639104796030676343" order="18" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainLossOnSaleOfPropertyPlantEquipment" xlink:label="us-gaap_GainLossOnSaleOfPropertyPlantEquipment_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities_639104796030467528" xlink:to="us-gaap_GainLossOnSaleOfPropertyPlantEquipment_639104796030676343" order="19" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivities_639104796030676343" order="2" use="optional" weight="1" priority="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities" xlink:label="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities_639104796030676343" xlink:to="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_639104796030676343" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt" xlink:label="us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities_639104796030676343" xlink:to="us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_639104796030676343" order="2" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseOfRestrictedInvestments" xlink:label="us-gaap_IncreaseDecreaseOfRestrictedInvestments_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities_639104796030676343" xlink:to="us-gaap_IncreaseDecreaseOfRestrictedInvestments_639104796030676343" order="3" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsToAcquireLoansHeldForInvestment" xlink:label="us-gaap_PaymentsToAcquireLoansHeldForInvestment_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities_639104796030676343" xlink:to="us-gaap_PaymentsToAcquireLoansHeldForInvestment_639104796030676343" order="4" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromLifeInsurancePolicies" xlink:label="us-gaap_ProceedsFromLifeInsurancePolicies_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities_639104796030676343" xlink:to="us-gaap_ProceedsFromLifeInsurancePolicies_639104796030676343" order="5" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities_639104796030676343" xlink:to="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_639104796030676343" order="6" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsToAcquireRealEstateHeldForInvestment" xlink:label="us-gaap_PaymentsToAcquireRealEstateHeldForInvestment_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities_639104796030676343" xlink:to="us-gaap_PaymentsToAcquireRealEstateHeldForInvestment_639104796030676343" order="7" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivities_639104796030676343" order="3" use="optional" weight="1" priority="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInDeposits" xlink:label="us-gaap_IncreaseDecreaseInDeposits_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities_639104796030676343" xlink:to="us-gaap_IncreaseDecreaseInDeposits_639104796030676343" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromRepaymentsOfShortTermDebt" xlink:label="us-gaap_ProceedsFromRepaymentsOfShortTermDebt_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities_639104796030676343" xlink:to="us-gaap_ProceedsFromRepaymentsOfShortTermDebt_639104796030676343" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromIssuanceOfSecuredDebt" xlink:label="us-gaap_ProceedsFromIssuanceOfSecuredDebt_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities_639104796030676343" xlink:to="us-gaap_ProceedsFromIssuanceOfSecuredDebt_639104796030676343" order="3" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RepaymentsOfLongTermDebt" xlink:label="us-gaap_RepaymentsOfLongTermDebt_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities_639104796030676343" xlink:to="us-gaap_RepaymentsOfLongTermDebt_639104796030676343" order="4" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="fkys-20251231.xsd#fkys_PaymentsOfOrdinaryDividendsCommonStockNetOfReinvestment" xlink:label="fkys_PaymentsOfOrdinaryDividendsCommonStockNetOfReinvestment_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities_639104796030676343" xlink:to="fkys_PaymentsOfOrdinaryDividendsCommonStockNetOfReinvestment_639104796030676343" order="5" use="optional" weight="-1" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.firstkeystonecorporation.com/role/DisclosureSecuritiesAmortizedCostRelatedEstimatedFairValueAndUnrealizedGainsAndLossesDetails" xlink:type="extended" xlink:title="99940201 - Disclosure - SECURITIES - Amortized cost, related estimated fair value, and unrealized gains and losses (Details)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss" xlink:to="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_639104796030676343" order="1" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss" xlink:to="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_639104796030676343" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="fkys-20251231.xsd#fkys_DebtSecuritiesAvailableForSaleAccumulatedBasisAdjustmentForFairValueHedge" xlink:label="fkys_DebtSecuritiesAvailableForSaleAccumulatedBasisAdjustmentForFairValueHedge_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss" xlink:to="fkys_DebtSecuritiesAvailableForSaleAccumulatedBasisAdjustmentForFairValueHedge_639104796030676343" order="3" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss" xlink:to="us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_639104796030676343" order="4" use="optional" weight="1" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.firstkeystonecorporation.com/role/DisclosureSecuritiesAgingOfAmortizedCostAndEstimatedFairValueOfDebtSecuritiesDetails" xlink:type="extended" xlink:title="99940202 - Disclosure - SECURITIES - Aging of amortized cost and estimated fair value of debt securities (Details)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis" xlink:label="AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis_639104796030676343" order="1" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis_639104796030676343" order="2" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis_639104796030676343" order="3" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis_639104796030676343" order="4" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate" xlink:label="AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue_639104796030676343" order="1" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue_639104796030676343" order="2" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue_639104796030676343" order="3" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue_639104796030676343" order="4" use="optional" weight="1" priority="2" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.firstkeystonecorporation.com/role/DisclosureSecuritiesContinuousUnrealizedLossPositionDetails" xlink:type="extended" xlink:title="99940204 - Disclosure - SECURITIES - Continuous unrealized loss position (Details)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition" xlink:to="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_639104796030676343" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition" xlink:to="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_639104796030676343" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss" xlink:to="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_639104796030676343" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss" xlink:to="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_639104796030676343" order="2" use="optional" weight="1" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.firstkeystonecorporation.com/role/DisclosureSecuritiesUnrealizedAndRealizedGainsLossesDetails" xlink:type="extended" xlink:title="99940205 - Disclosure - SECURITIES - Unrealized and realized gains (losses) (Details)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss" xlink:label="us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquitySecuritiesFvNiRealizedGainLoss" xlink:label="us-gaap_EquitySecuritiesFvNiRealizedGainLoss_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss" xlink:to="us-gaap_EquitySecuritiesFvNiRealizedGainLoss_639104796030676343" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MarketableSecuritiesGainLossExcludingOtherThanTemporaryImpairments" xlink:label="us-gaap_MarketableSecuritiesGainLossExcludingOtherThanTemporaryImpairments_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss" xlink:to="us-gaap_MarketableSecuritiesGainLossExcludingOtherThanTemporaryImpairments_639104796030676343" order="2" use="optional" weight="1" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.firstkeystonecorporation.com/role/DisclosureLoansAndAllowanceForCreditLossesOutstandingLoanBalancesByLoanClassPriorToAllocationOfNetDeferredFeesAndCostsDetails" xlink:type="extended" xlink:title="99940301 - Disclosure - LOANS AND ALLOWANCE FOR CREDIT LOSSES - Outstanding loan balances by loan class prior to allocation of net deferred fees and costs (Details)">
    <link:loc xlink:type="locator" xlink:href="fkys-20251231.xsd#fkys_LoansAndLeasesReceivableHeldForInvestmentNetOfDeferredIncome" xlink:label="fkys_LoansAndLeasesReceivableHeldForInvestmentNetOfDeferredIncome_1" />
    <link:loc xlink:type="locator" xlink:href="fkys-20251231.xsd#fkys_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLossAndDeferredFeesAndCosts" xlink:label="fkys_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLossAndDeferredFeesAndCosts_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="fkys_LoansAndLeasesReceivableHeldForInvestmentNetOfDeferredIncome_1" xlink:to="fkys_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLossAndDeferredFeesAndCosts_639104796030676343" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="fkys-20251231.xsd#fkys_FinancingReceivableDeferredFeesAndCostsExcludingAccruedInterest" xlink:label="fkys_FinancingReceivableDeferredFeesAndCostsExcludingAccruedInterest_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="fkys_LoansAndLeasesReceivableHeldForInvestmentNetOfDeferredIncome_1" xlink:to="fkys_FinancingReceivableDeferredFeesAndCostsExcludingAccruedInterest_639104796030676343" order="2" use="optional" weight="1" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.firstkeystonecorporation.com/role/DisclosureLoansAndAllowanceForCreditLossesClassesOfLoanPortfolioSummarizedByRiskRatingAndYearOfOriginationAndYearToDateGrossChargeOffsDetails" xlink:type="extended" xlink:title="99940302 - Disclosure - LOANS AND ALLOWANCE FOR CREDIT LOSSES - Classes of loan portfolio summarized by risk rating and year of origination and year-to-date gross charge-offs (Details)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff" xlink:label="us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff_1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearWriteoff" xlink:label="us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearWriteoff_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff_1" xlink:to="us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearWriteoff_639104796030676343" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff" xlink:label="us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff_1" xlink:to="us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff_639104796030676343" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff" xlink:label="us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff_1" xlink:to="us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff_639104796030676343" order="3" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff" xlink:label="us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff_1" xlink:to="us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff_639104796030676343" order="4" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff" xlink:label="us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff_1" xlink:to="us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff_639104796030676343" order="5" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearWriteoff" xlink:label="us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearWriteoff_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff_1" xlink:to="us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearWriteoff_639104796030676343" order="6" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss" xlink:label="us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear" xlink:label="us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss" xlink:to="us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear_639104796030676343" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear" xlink:label="us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss" xlink:to="us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear_639104796030676343" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear" xlink:label="us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss" xlink:to="us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear_639104796030676343" order="3" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear" xlink:label="us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss" xlink:to="us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear_639104796030676343" order="4" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear" xlink:label="us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss" xlink:to="us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear_639104796030676343" order="5" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear" xlink:label="us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss" xlink:to="us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear_639104796030676343" order="6" use="optional" weight="1" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.firstkeystonecorporation.com/role/DisclosureLoansAndAllowanceForCreditLossesNonPerformingAssetsDetails" xlink:type="extended" xlink:title="99940310 - Disclosure - LOANS AND ALLOWANCE FOR CREDIT LOSSES - Non-performing assets (Details)">
    <link:loc xlink:type="locator" xlink:href="fkys-20251231.xsd#fkys_NonPerformingAssets" xlink:label="NonPerformingAssets" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="NonPerformingAssets" xlink:to="us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus_639104796030676343" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing" xlink:label="us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="NonPerformingAssets" xlink:to="us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing_639104796030676343" order="2" use="optional" weight="1" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.firstkeystonecorporation.com/role/DisclosurePremisesAndEquipmentNetDetails" xlink:type="extended" xlink:title="99940401 - Disclosure - PREMISES AND EQUIPMENT, NET (Details)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization" xlink:label="PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization" xlink:label="us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization" xlink:to="us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization_639104796030676343" order="1" use="optional" weight="-1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization" xlink:label="us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization" xlink:to="us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization_639104796030676343" order="2" use="optional" weight="1" priority="2" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.firstkeystonecorporation.com/role/DisclosureDepositsDetails" xlink:type="extended" xlink:title="99940501 - Disclosure - DEPOSITS (Details)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Deposits" xlink:label="Deposits" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NoninterestBearingDomesticDepositDemand" xlink:label="us-gaap_NoninterestBearingDomesticDepositDemand_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="Deposits" xlink:to="us-gaap_NoninterestBearingDomesticDepositDemand_639104796030676343" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestBearingDomesticDepositDemand" xlink:label="us-gaap_InterestBearingDomesticDepositDemand_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="Deposits" xlink:to="us-gaap_InterestBearingDomesticDepositDemand_639104796030676343" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DepositsSavingsDeposits" xlink:label="us-gaap_DepositsSavingsDeposits_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="Deposits" xlink:to="us-gaap_DepositsSavingsDeposits_639104796030676343" order="3" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="fkys-20251231.xsd#fkys_TimeDepositsLessThan250000" xlink:label="fkys_TimeDepositsLessThan250000_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="Deposits" xlink:to="fkys_TimeDepositsLessThan250000_639104796030676343" order="4" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="fkys-20251231.xsd#fkys_TimeDeposits250000OrMore" xlink:label="fkys_TimeDeposits250000OrMore_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="Deposits" xlink:to="fkys_TimeDeposits250000OrMore_639104796030676343" order="5" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="fkys-20251231.xsd#fkys_OtherTime" xlink:label="fkys_OtherTime_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="Deposits" xlink:to="fkys_OtherTime_639104796030676343" order="6" use="optional" weight="1" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.firstkeystonecorporation.com/role/DisclosureDepositsMaturitiesOfTimeDepositsDetails" xlink:type="extended" xlink:title="99940502 - Disclosure - DEPOSITS - Maturities of time deposits (Details)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TimeDepositLiabilityAboveUsInsuranceLimit" xlink:label="us-gaap_TimeDepositLiabilityAboveUsInsuranceLimit" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TimeDepositLiabilityAboveUsInsuranceLimitMaturityOver12Months" xlink:label="us-gaap_TimeDepositLiabilityAboveUsInsuranceLimitMaturityOver12Months_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_TimeDepositLiabilityAboveUsInsuranceLimit" xlink:to="us-gaap_TimeDepositLiabilityAboveUsInsuranceLimitMaturityOver12Months_639104796030676343" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TimeDepositLiabilityAboveUsInsuranceLimitMaturityOverSixMonthsThroughTwelveMonths" xlink:label="us-gaap_TimeDepositLiabilityAboveUsInsuranceLimitMaturityOverSixMonthsThroughTwelveMonths_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_TimeDepositLiabilityAboveUsInsuranceLimit" xlink:to="us-gaap_TimeDepositLiabilityAboveUsInsuranceLimitMaturityOverSixMonthsThroughTwelveMonths_639104796030676343" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TimeDepositLiabilityAboveUsInsuranceLimitMaturityThreeMonthsOrLess" xlink:label="us-gaap_TimeDepositLiabilityAboveUsInsuranceLimitMaturityThreeMonthsOrLess_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_TimeDepositLiabilityAboveUsInsuranceLimit" xlink:to="us-gaap_TimeDepositLiabilityAboveUsInsuranceLimitMaturityThreeMonthsOrLess_639104796030676343" order="3" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TimeDepositLiabilityAboveUsInsuranceLimitMaturityOverThreeMonthsThroughSixMonths" xlink:label="us-gaap_TimeDepositLiabilityAboveUsInsuranceLimitMaturityOverThreeMonthsThroughSixMonths_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_TimeDepositLiabilityAboveUsInsuranceLimit" xlink:to="us-gaap_TimeDepositLiabilityAboveUsInsuranceLimitMaturityOverThreeMonthsThroughSixMonths_639104796030676343" order="4" use="optional" weight="1" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.firstkeystonecorporation.com/role/DisclosureDepositsSummaryOfClassificationAndRemainingMaturitiesOfTimeDepositsDetails" xlink:type="extended" xlink:title="99940503 - Disclosure - DEPOSITS - Summary of classification and remaining maturities of time deposits (Details)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TimeDeposits" xlink:label="TimeDeposits" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TimeDepositMaturitiesYearOne" xlink:label="us-gaap_TimeDepositMaturitiesYearOne_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="TimeDeposits" xlink:to="us-gaap_TimeDepositMaturitiesYearOne_639104796030676343" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TimeDepositMaturitiesYearTwo" xlink:label="us-gaap_TimeDepositMaturitiesYearTwo_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="TimeDeposits" xlink:to="us-gaap_TimeDepositMaturitiesYearTwo_639104796030676343" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TimeDepositMaturitiesYearThree" xlink:label="us-gaap_TimeDepositMaturitiesYearThree_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="TimeDeposits" xlink:to="us-gaap_TimeDepositMaturitiesYearThree_639104796030676343" order="3" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TimeDepositMaturitiesYearFour" xlink:label="us-gaap_TimeDepositMaturitiesYearFour_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="TimeDeposits" xlink:to="us-gaap_TimeDepositMaturitiesYearFour_639104796030676343" order="4" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TimeDepositMaturitiesYearFive" xlink:label="us-gaap_TimeDepositMaturitiesYearFive_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="TimeDeposits" xlink:to="us-gaap_TimeDepositMaturitiesYearFive_639104796030676343" order="5" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TimeDepositMaturitiesAfterYearFive" xlink:label="us-gaap_TimeDepositMaturitiesAfterYearFive_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="TimeDeposits" xlink:to="us-gaap_TimeDepositMaturitiesAfterYearFive_639104796030676343" order="6" use="optional" weight="1" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.firstkeystonecorporation.com/role/DisclosureShortTermBorrowingsRepurchaseAgreementsDetails" xlink:type="extended" xlink:title="99940602 - Disclosure - SHORT-TERM BORROWINGS - Repurchase agreements (Details)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SecuritiesSoldUnderAgreementsToRepurchase" xlink:label="SecuritiesSoldUnderAgreementsToRepurchase" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseGross" xlink:label="us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseGross_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="SecuritiesSoldUnderAgreementsToRepurchase" xlink:to="us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseGross_639104796030676343" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SecuritySoldUnderAgreementToRepurchaseAfterOffsetAndDeductionSubjectToMasterNettingArrangement" xlink:label="us-gaap_SecuritySoldUnderAgreementToRepurchaseAfterOffsetAndDeductionSubjectToMasterNettingArrangement" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseCollateralRightToReclaimCash" xlink:label="us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseCollateralRightToReclaimCash_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_SecuritySoldUnderAgreementToRepurchaseAfterOffsetAndDeductionSubjectToMasterNettingArrangement" xlink:to="us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseCollateralRightToReclaimCash_639104796030676343" order="1" use="optional" weight="-1" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.firstkeystonecorporation.com/role/DisclosureCommitmentsAndContingenciesMaturityAnalysisOfOperatingLeaseLiabilitiesCalc2Details" xlink:type="extended" xlink:title="40802 - Disclosure - COMMITMENTS AND CONTINGENCIES - Maturity analysis of operating lease liabilities - Calc 2 (Details)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDue" xlink:label="us-gaap_FinanceLeaseLiabilityPaymentsDue_1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" xlink:label="us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_FinanceLeaseLiabilityPaymentsDue_1" xlink:to="us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount_639104796030676343" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseLiability" xlink:label="us-gaap_FinanceLeaseLiability_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_FinanceLeaseLiabilityPaymentsDue_1" xlink:to="us-gaap_FinanceLeaseLiability_639104796030676343" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_639104796030676343" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseLiability" xlink:label="us-gaap_OperatingLeaseLiability_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="us-gaap_OperatingLeaseLiability_639104796030676343" order="2" use="optional" weight="1" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.firstkeystonecorporation.com/role/DisclosureIncomeTaxesIncomeTaxesPaidDetails" xlink:type="extended" xlink:title="99940901 - Disclosure - INCOME TAXES - Income taxes paid (Details)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxesPaid" xlink:label="us-gaap_IncomeTaxesPaid" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxPaidFederalBeforeRefundReceived" xlink:label="us-gaap_IncomeTaxPaidFederalBeforeRefundReceived_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_IncomeTaxesPaid" xlink:to="us-gaap_IncomeTaxPaidFederalBeforeRefundReceived_639104796030676343" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxPaidStateAndLocalBeforeRefundReceived" xlink:label="us-gaap_IncomeTaxPaidStateAndLocalBeforeRefundReceived_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_IncomeTaxesPaid" xlink:to="us-gaap_IncomeTaxPaidStateAndLocalBeforeRefundReceived_639104796030676343" order="2" use="optional" weight="1" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.firstkeystonecorporation.com/role/DisclosureIncomeTaxesSummaryOfCurrentAndDeferredComponentsDetails" xlink:type="extended" xlink:title="99940902 - Disclosure - INCOME TAXES - Summary of current and deferred components (Details)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="us-gaap_IncomeTaxExpenseBenefit_1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CurrentIncomeTaxExpenseBenefit" xlink:label="us-gaap_CurrentIncomeTaxExpenseBenefit_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_IncomeTaxExpenseBenefit_1" xlink:to="us-gaap_CurrentIncomeTaxExpenseBenefit_639104796030676343" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CurrentFederalTaxExpenseBenefit" xlink:label="us-gaap_CurrentFederalTaxExpenseBenefit_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_CurrentIncomeTaxExpenseBenefit_639104796030676343" xlink:to="us-gaap_CurrentFederalTaxExpenseBenefit_639104796030676343" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CurrentStateAndLocalTaxExpenseBenefit" xlink:label="us-gaap_CurrentStateAndLocalTaxExpenseBenefit_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_CurrentIncomeTaxExpenseBenefit_639104796030676343" xlink:to="us-gaap_CurrentStateAndLocalTaxExpenseBenefit_639104796030676343" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:label="us-gaap_DeferredIncomeTaxExpenseBenefit_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_IncomeTaxExpenseBenefit_1" xlink:to="us-gaap_DeferredIncomeTaxExpenseBenefit_639104796030676343" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredFederalIncomeTaxExpenseBenefit" xlink:label="us-gaap_DeferredFederalIncomeTaxExpenseBenefit_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_DeferredIncomeTaxExpenseBenefit_639104796030676343" xlink:to="us-gaap_DeferredFederalIncomeTaxExpenseBenefit_639104796030676343" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit" xlink:label="us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit_639104796030676343" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_DeferredIncomeTaxExpenseBenefit_639104796030676343" xlink:to="us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit_639104796030676343" order="2" use="optional" weight="1" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.firstkeystonecorporation.com/role/DisclosureIncomeTaxesSummaryOfReconciliationBetweenIncomeTaxBenefitExpenseAndAmountOfIncomeTaxesDetails" xlink:type="extended" xlink:title="99940903 - Disclosure - INCOME TAXES - Summary of reconciliation between the income tax (benefit) expense and the amount of income taxes (Details)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:label="EffectiveIncomeTaxRateContinuingOperations" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="EffectiveIncomeTaxRateContinuingOperations" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_639104796030781831" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="EffectiveIncomeTaxRateContinuingOperations" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes_639104796030781831" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseOther" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseOther_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="EffectiveIncomeTaxRateContinuingOperations" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseOther_639104796030781831" order="3" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="EffectiveIncomeTaxRateContinuingOperations" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments_639104796030781831" order="4" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationTaxExemptIncome" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationTaxExemptIncome_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="EffectiveIncomeTaxRateContinuingOperations" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationTaxExemptIncome_639104796030781831" order="5" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationTaxCreditsInvestment" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationTaxCreditsInvestment_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="EffectiveIncomeTaxRateContinuingOperations" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationTaxCreditsInvestment_639104796030781831" order="6" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="fkys-20251231.xsd#fkys_BankOwnedLifeInsuranceIncomePercent" xlink:label="fkys_BankOwnedLifeInsuranceIncomePercent_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="EffectiveIncomeTaxRateContinuingOperations" xlink:to="fkys_BankOwnedLifeInsuranceIncomePercent_639104796030781831" order="7" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationPriorYearIncomeTaxes" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationPriorYearIncomeTaxes_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="EffectiveIncomeTaxRateContinuingOperations" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationPriorYearIncomeTaxes_639104796030781831" order="8" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseImpairmentLosses" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseImpairmentLosses_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="EffectiveIncomeTaxRateContinuingOperations" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseImpairmentLosses_639104796030781831" order="9" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="us-gaap_IncomeTaxExpenseBenefit" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxReconciliationPriorYearIncomeTaxes" xlink:label="us-gaap_IncomeTaxReconciliationPriorYearIncomeTaxes_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_IncomeTaxExpenseBenefit" xlink:to="us-gaap_IncomeTaxReconciliationPriorYearIncomeTaxes_639104796030781831" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxReconciliationNondeductibleExpenseImpairmentLosses" xlink:label="us-gaap_IncomeTaxReconciliationNondeductibleExpenseImpairmentLosses_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_IncomeTaxExpenseBenefit" xlink:to="us-gaap_IncomeTaxReconciliationNondeductibleExpenseImpairmentLosses_639104796030781831" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="fkys-20251231.xsd#fkys_EffectiveIncomeTaxRateReconciliationIncomeLifeInsuranceAmount" xlink:label="fkys_EffectiveIncomeTaxRateReconciliationIncomeLifeInsuranceAmount_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_IncomeTaxExpenseBenefit" xlink:to="fkys_EffectiveIncomeTaxRateReconciliationIncomeLifeInsuranceAmount_639104796030781831" order="3" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxReconciliationTaxCreditsInvestment" xlink:label="us-gaap_IncomeTaxReconciliationTaxCreditsInvestment_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_IncomeTaxExpenseBenefit" xlink:to="us-gaap_IncomeTaxReconciliationTaxCreditsInvestment_639104796030781831" order="4" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxReconciliationOtherAdjustments" xlink:label="us-gaap_IncomeTaxReconciliationOtherAdjustments_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_IncomeTaxExpenseBenefit" xlink:to="us-gaap_IncomeTaxReconciliationOtherAdjustments_639104796030781831" order="5" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes" xlink:label="us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_IncomeTaxExpenseBenefit" xlink:to="us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes_639104796030781831" order="6" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxReconciliationNondeductibleExpenseOther" xlink:label="us-gaap_IncomeTaxReconciliationNondeductibleExpenseOther_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_IncomeTaxExpenseBenefit" xlink:to="us-gaap_IncomeTaxReconciliationNondeductibleExpenseOther_639104796030781831" order="7" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxReconciliationTaxExemptIncome" xlink:label="us-gaap_IncomeTaxReconciliationTaxExemptIncome_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_IncomeTaxExpenseBenefit" xlink:to="us-gaap_IncomeTaxReconciliationTaxExemptIncome_639104796030781831" order="8" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate" xlink:label="us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_IncomeTaxExpenseBenefit" xlink:to="us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate_639104796030781831" order="9" use="optional" weight="1" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.firstkeystonecorporation.com/role/DisclosureIncomeTaxesSummaryOfComponentsOfNetDeferredTaxAssetAndLiabilitiesDetails" xlink:type="extended" xlink:title="99940904 - Disclosure - INCOME TAXES - Summary of components of the net deferred tax asset and liabilities (Details)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredTaxAssetsLiabilitiesNet" xlink:label="DeferredTaxAssetsLiabilitiesNet" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredTaxAssetsNet" xlink:label="us-gaap_DeferredTaxAssetsNet_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="DeferredTaxAssetsLiabilitiesNet" xlink:to="us-gaap_DeferredTaxAssetsNet_639104796030781831" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredIncomeTaxLiabilities" xlink:label="us-gaap_DeferredIncomeTaxLiabilities_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="DeferredTaxAssetsLiabilitiesNet" xlink:to="us-gaap_DeferredIncomeTaxLiabilities_639104796030781831" order="2" use="optional" weight="-1" priority="2" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.firstkeystonecorporation.com/role/DisclosureCommitmentsAndContingenciesMaturityAnalysisOfOperatingAndFinanceLeaseLiabilitiesDetails" xlink:type="extended" xlink:title="99941103 - Disclosure - COMMITMENTS AND CONTINGENCIES - Maturity analysis of Operating and Finance lease liabilities (Details)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDue" xlink:label="us-gaap_FinanceLeaseLiabilityPaymentsDue" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueInNextRollingTwelveMonths" xlink:label="us-gaap_FinanceLeaseLiabilityPaymentsDueInNextRollingTwelveMonths_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_FinanceLeaseLiabilityPaymentsDue" xlink:to="us-gaap_FinanceLeaseLiabilityPaymentsDueInNextRollingTwelveMonths_639104796030781831" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueInRollingYearTwo" xlink:label="us-gaap_FinanceLeaseLiabilityPaymentsDueInRollingYearTwo_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_FinanceLeaseLiabilityPaymentsDue" xlink:to="us-gaap_FinanceLeaseLiabilityPaymentsDueInRollingYearTwo_639104796030781831" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueInRollingYearThree" xlink:label="us-gaap_FinanceLeaseLiabilityPaymentsDueInRollingYearThree_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_FinanceLeaseLiabilityPaymentsDue" xlink:to="us-gaap_FinanceLeaseLiabilityPaymentsDueInRollingYearThree_639104796030781831" order="3" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueInRollingYearFour" xlink:label="us-gaap_FinanceLeaseLiabilityPaymentsDueInRollingYearFour_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_FinanceLeaseLiabilityPaymentsDue" xlink:to="us-gaap_FinanceLeaseLiabilityPaymentsDueInRollingYearFour_639104796030781831" order="4" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueInRollingYearFive" xlink:label="us-gaap_FinanceLeaseLiabilityPaymentsDueInRollingYearFive_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_FinanceLeaseLiabilityPaymentsDue" xlink:to="us-gaap_FinanceLeaseLiabilityPaymentsDueInRollingYearFive_639104796030781831" order="5" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextRollingTwelveMonths" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextRollingTwelveMonths_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_1" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextRollingTwelveMonths_639104796030781831" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearTwo" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearTwo_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_1" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearTwo_639104796030781831" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearThree" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearThree_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_1" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearThree_639104796030781831" order="3" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearFour" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearFour_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_1" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearFour_639104796030781831" order="4" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearFive" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearFive_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_1" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearFive_639104796030781831" order="5" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterRollingYearFive" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterRollingYearFive_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_1" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterRollingYearFive_639104796030781831" order="6" use="optional" weight="1" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.firstkeystonecorporation.com/role/DisclosureDerivativeInstrumentsAndHedgingActivitiesMasterNettingArrangementsDetails" xlink:type="extended" xlink:title="99941203 - Disclosure - DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Master Netting Arrangements (Details)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeLiabilityFairValueAfterOffsetAndDeductionSubjectToMasterNettingArrangement" xlink:label="us-gaap_DerivativeLiabilityFairValueAfterOffsetAndDeductionSubjectToMasterNettingArrangement" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeLiabilities" xlink:label="us-gaap_DerivativeLiabilities_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_DerivativeLiabilityFairValueAfterOffsetAndDeductionSubjectToMasterNettingArrangement" xlink:to="us-gaap_DerivativeLiabilities_639104796030781831" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeCollateralRightToReclaimCash" xlink:label="us-gaap_DerivativeCollateralRightToReclaimCash_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_DerivativeLiabilityFairValueAfterOffsetAndDeductionSubjectToMasterNettingArrangement" xlink:to="us-gaap_DerivativeCollateralRightToReclaimCash_639104796030781831" order="2" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeFairValueOfDerivativeLiabilityAmountNotOffsetAgainstCollateral" xlink:label="us-gaap_DerivativeFairValueOfDerivativeLiabilityAmountNotOffsetAgainstCollateral_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_DerivativeLiabilityFairValueAfterOffsetAndDeductionSubjectToMasterNettingArrangement" xlink:to="us-gaap_DerivativeFairValueOfDerivativeLiabilityAmountNotOffsetAgainstCollateral_639104796030781831" order="3" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="fkys-20251231.xsd#fkys_NetContractualObligation" xlink:label="fkys_NetContractualObligation" />
    <link:loc xlink:type="locator" xlink:href="fkys-20251231.xsd#fkys_ContractualObligationToBePaidYearOneToYearThree" xlink:label="fkys_ContractualObligationToBePaidYearOneToYearThree_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="fkys_NetContractualObligation" xlink:to="fkys_ContractualObligationToBePaidYearOneToYearThree_639104796030781831" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractualObligationDueAfterFifthYear" xlink:label="us-gaap_ContractualObligationDueAfterFifthYear_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="fkys_NetContractualObligation" xlink:to="us-gaap_ContractualObligationDueAfterFifthYear_639104796030781831" order="2" use="optional" weight="1" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.firstkeystonecorporation.com/role/DisclosureFairValueMeasurementsDetails" xlink:type="extended" xlink:title="99941701 - Disclosure - FAIR VALUE MEASUREMENTS (Details)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MarketableSecurities" xlink:label="MarketableSecurities" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="MarketableSecurities" xlink:to="us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_639104796030781831" order="1" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquitySecuritiesFvNi" xlink:label="us-gaap_EquitySecuritiesFvNi_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="MarketableSecurities" xlink:to="us-gaap_EquitySecuritiesFvNi_639104796030781831" order="2" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeLiabilities" xlink:label="us-gaap_DerivativeLiabilities_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="MarketableSecurities" xlink:to="us-gaap_DerivativeLiabilities_639104796030781831" order="3" use="optional" weight="-1" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.firstkeystonecorporation.com/role/DisclosureParentCompanyFinancialInformationBalanceSheetsDetails" xlink:type="extended" xlink:title="99942001 - Disclosure - PARENT COMPANY FINANCIAL INFORMATION (BALANCE SHEETS) (Details)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Assets" xlink:label="Assets" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Cash" xlink:label="us-gaap_Cash_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="Assets" xlink:to="us-gaap_Cash_639104796030781831" order="1" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquitySecuritiesFvNi" xlink:label="us-gaap_EquitySecuritiesFvNi_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="Assets" xlink:to="us-gaap_EquitySecuritiesFvNi_639104796030781831" order="2" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:label="us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="Assets" xlink:to="us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_639104796030781831" order="3" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PrepaidExpenseAndOtherAssets" xlink:label="us-gaap_PrepaidExpenseAndOtherAssets_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="Assets" xlink:to="us-gaap_PrepaidExpenseAndOtherAssets_639104796030781831" order="4" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Liabilities" xlink:label="Liabilities" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccruedLiabilitiesAndOtherLiabilities" xlink:label="us-gaap_AccruedLiabilitiesAndOtherLiabilities_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="Liabilities" xlink:to="us-gaap_AccruedLiabilitiesAndOtherLiabilities_639104796030781831" order="1" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherLiabilities" xlink:label="us-gaap_OtherLiabilities_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="Liabilities" xlink:to="us-gaap_OtherLiabilities_639104796030781831" order="2" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubordinatedDebt" xlink:label="us-gaap_SubordinatedDebt_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="Liabilities" xlink:to="us-gaap_SubordinatedDebt_639104796030781831" order="3" use="optional" weight="1" priority="2" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.firstkeystonecorporation.com/role/DisclosureParentCompanyFinancialInformationStatementsOfIncomeLossDetails" xlink:type="extended" xlink:title="99942002 - Disclosure - PARENT COMPANY FINANCIAL INFORMATION (STATEMENTS OF INCOME (LOSS)) (Details)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss" xlink:label="NetIncomeLoss" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromSubsidiariesNetOfTax" xlink:label="us-gaap_IncomeLossFromSubsidiariesNetOfTax_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="NetIncomeLoss" xlink:to="us-gaap_IncomeLossFromSubsidiariesNetOfTax_639104796030781831" order="1" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="fkys-20251231.xsd#fkys_IncomeLossFromContinuingOperationsBeforeIncomeLossFromEquityMethodInvestments" xlink:label="fkys_IncomeLossFromContinuingOperationsBeforeIncomeLossFromEquityMethodInvestments_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="NetIncomeLoss" xlink:to="fkys_IncomeLossFromContinuingOperationsBeforeIncomeLossFromEquityMethodInvestments_639104796030781831" order="2" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingExpenses" xlink:label="OperatingExpenses" />
    <link:loc xlink:type="locator" xlink:href="fkys-20251231.xsd#fkys_InterestExpenseSubordinatedDebentures" xlink:label="fkys_InterestExpenseSubordinatedDebentures_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="OperatingExpenses" xlink:to="fkys_InterestExpenseSubordinatedDebentures_639104796030781831" order="1" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherExpenses" xlink:label="us-gaap_OtherExpenses_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="OperatingExpenses" xlink:to="us-gaap_OtherExpenses_639104796030781831" order="2" use="optional" weight="1" priority="2" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.firstkeystonecorporation.com/role/DisclosureParentCompanyFinancialInformationStatementsOfCashFlowsDetails" xlink:type="extended" xlink:title="99942004 - Disclosure - PARENT COMPANY FINANCIAL INFORMATION (STATEMENTS OF CASH FLOWS) (Details)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="NetCashProvidedByUsedInOperatingActivities" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss" xlink:label="us-gaap_NetIncomeLoss_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="NetCashProvidedByUsedInOperatingActivities" xlink:to="us-gaap_NetIncomeLoss_639104796030781831" order="1" use="optional" weight="1" priority="3" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:label="us-gaap_DeferredIncomeTaxExpenseBenefit_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="NetCashProvidedByUsedInOperatingActivities" xlink:to="us-gaap_DeferredIncomeTaxExpenseBenefit_639104796030781831" order="2" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss" xlink:label="us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="NetCashProvidedByUsedInOperatingActivities" xlink:to="us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss_639104796030781831" order="3" use="optional" weight="-1" priority="3" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromSubsidiariesNetOfTax" xlink:label="us-gaap_IncomeLossFromSubsidiariesNetOfTax_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="NetCashProvidedByUsedInOperatingActivities" xlink:to="us-gaap_IncomeLossFromSubsidiariesNetOfTax_639104796030781831" order="4" use="optional" weight="-1" priority="3" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInDueToRelatedParties" xlink:label="us-gaap_IncreaseDecreaseInDueToRelatedParties_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="NetCashProvidedByUsedInOperatingActivities" xlink:to="us-gaap_IncreaseDecreaseInDueToRelatedParties_639104796030781831" order="5" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:label="us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_639104796030781831" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="NetCashProvidedByUsedInOperatingActivities" xlink:to="us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_639104796030781831" order="6" use="optional" weight="-1" priority="3" />
  </link:calculationLink>
</link:linkbase>
