<?xml version="1.0" encoding="US-ASCII" standalone="no"?>
    <!-- Field: Doc-Info; Name: Generator; Value: GoFiler Complete; Version: 6.4a -->
    <!-- Field: Doc-Info; Name: VendorURI; Value: https://www.novaworks.com -->
    <!-- Field: Doc-Info; Name: Status; Value: 0x00000000 -->
<link:linkbase xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrli="http://www.xbrl.org/2003/instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#Cover" roleURI="http://surocap.com/role/Cover" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#StatementsOfAssetsAndLiabilities" roleURI="http://surocap.com/role/StatementsOfAssetsAndLiabilities" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#StatementsOfAssetsAndLiabilitiesParenthetical" roleURI="http://surocap.com/role/StatementsOfAssetsAndLiabilitiesParenthetical" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#StatementsOfOperations" roleURI="http://surocap.com/role/StatementsOfOperations" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#StatementsOfOperationsParenthetical" roleURI="http://surocap.com/role/StatementsOfOperationsParenthetical" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#StatementsOfChangesInNetAssets" roleURI="http://surocap.com/role/StatementsOfChangesInNetAssets" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#StatementsOfCashFlows" roleURI="http://surocap.com/role/StatementsOfCashFlows" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#StatementsOfCashFlowsParenthetical" roleURI="http://surocap.com/role/StatementsOfCashFlowsParenthetical" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfInvestments" roleURI="http://surocap.com/role/ScheduleOfInvestments" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfInvestmentsParenthetical" roleURI="http://surocap.com/role/ScheduleOfInvestmentsParenthetical" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/cyd/2025/cyd-2025.xsd#CybersecurityRiskManagementAndStrategyDisclosure" roleURI="http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/cyd/2025/cyd-2025.xsd#MaterialCybersecurityIncidentDisclosure" roleURI="http://xbrl.sec.gov/cyd/role/MaterialCybersecurityIncidentDisclosure" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#NatureOfOperations" roleURI="http://surocap.com/role/NatureOfOperations" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#SignificantAccountingPolicies" roleURI="http://surocap.com/role/SignificantAccountingPolicies" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#Related-partyArrangements" roleURI="http://surocap.com/role/Related-partyArrangements" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#InvestmentsAtFairValue" roleURI="http://surocap.com/role/InvestmentsAtFairValue" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#CommonStock" roleURI="http://surocap.com/role/CommonStock" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#NetChangeInNetAssetsResultingFromOperationsPerCommonSharebasicAndDiluted" roleURI="http://surocap.com/role/NetChangeInNetAssetsResultingFromOperationsPerCommonSharebasicAndDiluted" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#CommitmentsAndContingencies" roleURI="http://surocap.com/role/CommitmentsAndContingencies" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#FinancialHighlights" roleURI="http://surocap.com/role/FinancialHighlights" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#IncomeTaxes" roleURI="http://surocap.com/role/IncomeTaxes" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#DebtCapitalActivities" roleURI="http://surocap.com/role/DebtCapitalActivities" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#Stock-basedCompensation" roleURI="http://surocap.com/role/Stock-basedCompensation" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#SubsequentEvents" roleURI="http://surocap.com/role/SubsequentEvents" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#SelectedQuarterlyFinancialData" roleURI="http://surocap.com/role/SelectedQuarterlyFinancialData" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#SupplementalFinancialData" roleURI="http://surocap.com/role/SupplementalFinancialData" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#SignificantAccountingPoliciesPolicies" roleURI="http://surocap.com/role/SignificantAccountingPoliciesPolicies" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#NatureOfOperationsTables" roleURI="http://surocap.com/role/NatureOfOperationsTables" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#SignificantAccountingPoliciesTables" roleURI="http://surocap.com/role/SignificantAccountingPoliciesTables" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#InvestmentsAtFairValueTables" roleURI="http://surocap.com/role/InvestmentsAtFairValueTables" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#CommonStockTables" roleURI="http://surocap.com/role/CommonStockTables" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#NetChangeInNetAssetsResultingFromOperationsPerCommonSharebasicAndDilutedTables" roleURI="http://surocap.com/role/NetChangeInNetAssetsResultingFromOperationsPerCommonSharebasicAndDilutedTables" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#CommitmentsAndContingenciesTables" roleURI="http://surocap.com/role/CommitmentsAndContingenciesTables" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#FinancialHighlightsTables" roleURI="http://surocap.com/role/FinancialHighlightsTables" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#IncomeTaxesTables" roleURI="http://surocap.com/role/IncomeTaxesTables" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#DebtCapitalActivitiesTables" roleURI="http://surocap.com/role/DebtCapitalActivitiesTables" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#Stock-basedCompensationTables" roleURI="http://surocap.com/role/Stock-basedCompensationTables" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#SubsequentEventsTables" roleURI="http://surocap.com/role/SubsequentEventsTables" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#SelectedQuarterlyFinancialDataTables" roleURI="http://surocap.com/role/SelectedQuarterlyFinancialDataTables" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfCompanysSubsidiariesDetails" roleURI="http://surocap.com/role/ScheduleOfCompanysSubsidiariesDetails" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfDeferredFinancingCostsDetails" roleURI="http://surocap.com/role/ScheduleOfDeferredFinancingCostsDetails" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#SignificantAccountingPoliciesDetailsNarrative" roleURI="http://surocap.com/role/SignificantAccountingPoliciesDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#Related-partyArrangementsDetailsNarrative" roleURI="http://surocap.com/role/Related-partyArrangementsDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfCompositionOfInvestmentPortfolioDetails" roleURI="http://surocap.com/role/ScheduleOfCompositionOfInvestmentPortfolioDetails" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfFairValueOfInvestmentValuationInputsDetails" roleURI="http://surocap.com/role/ScheduleOfFairValueOfInvestmentValuationInputsDetails" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfFairValueOfAssetsOnUnobservableInputDetails" roleURI="http://surocap.com/role/ScheduleOfFairValueOfAssetsOnUnobservableInputDetails" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfAggregateValueOfAssetsAndLiabilitiesDetails" roleURI="http://surocap.com/role/ScheduleOfAggregateValueOfAssetsAndLiabilitiesDetails" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfAggregateValueOfAssetsAndLiabilitiesDetailsParenthetical" roleURI="http://surocap.com/role/ScheduleOfAggregateValueOfAssetsAndLiabilitiesDetailsParenthetical" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfInvestmentsInAndAdvancesToAffiliatesDetails" roleURI="http://surocap.com/role/ScheduleOfInvestmentsInAndAdvancesToAffiliatesDetails" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfInvestmentsInAndAdvancesToAffiliatesDetailsParenthetical" roleURI="http://surocap.com/role/ScheduleOfInvestmentsInAndAdvancesToAffiliatesDetailsParenthetical" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#InvestmentsAtFairValueDetailsNarrative" roleURI="http://surocap.com/role/InvestmentsAtFairValueDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfSharesSoldUnderAtmProgramDetails" roleURI="http://surocap.com/role/ScheduleOfSharesSoldUnderAtmProgramDetails" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#CommonStockDetailsNarrative" roleURI="http://surocap.com/role/CommonStockDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfBasicAndDilutedCommonShareDetails" roleURI="http://surocap.com/role/ScheduleOfBasicAndDilutedCommonShareDetails" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfBasicAndDilutedCommonShareDetailsParenthetical" roleURI="http://surocap.com/role/ScheduleOfBasicAndDilutedCommonShareDetailsParenthetical" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfFutureMinimumPaymentsOfOperationLeaseDetails" roleURI="http://surocap.com/role/ScheduleOfFutureMinimumPaymentsOfOperationLeaseDetails" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#CommitmentsAndContingenciesDetailsNarrative" roleURI="http://surocap.com/role/CommitmentsAndContingenciesDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfFinancialHighlightsDetails" roleURI="http://surocap.com/role/ScheduleOfFinancialHighlightsDetails" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfFinancialHighlightsDetailsParenthetical" roleURI="http://surocap.com/role/ScheduleOfFinancialHighlightsDetailsParenthetical" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfEffectiveIncomeTaxRateReconciliationDetails" roleURI="http://surocap.com/role/ScheduleOfEffectiveIncomeTaxRateReconciliationDetails" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfFederalIncomeTaxDetails" roleURI="http://surocap.com/role/ScheduleOfFederalIncomeTaxDetails" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfAggregateIncomeTaxDetails" roleURI="http://surocap.com/role/ScheduleOfAggregateIncomeTaxDetails" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfProvisionForIncomeTaxesDetails" roleURI="http://surocap.com/role/ScheduleOfProvisionForIncomeTaxesDetails" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfReclassificationOfBooktaxDifferencesDetails" roleURI="http://surocap.com/role/ScheduleOfReclassificationOfBooktaxDifferencesDetails" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfTaxCharacterOfDistributionsDetails" roleURI="http://surocap.com/role/ScheduleOfTaxCharacterOfDistributionsDetails" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfComponentsOfDistributedEarningsOnTaxBasisDetails" roleURI="http://surocap.com/role/ScheduleOfComponentsOfDistributedEarningsOnTaxBasisDetails" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#IncomeTaxesDetailsNarrative" roleURI="http://surocap.com/role/IncomeTaxesDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfReconciliationFromAggregatePrincipalAmountOf6.00NotesDue2026Details" roleURI="http://surocap.com/role/ScheduleOfReconciliationFromAggregatePrincipalAmountOf6.00NotesDue2026Details" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfReconciliationFromAggregatePrincipalAmountOf6.50ConvertibleNotesDue2029Details" roleURI="http://surocap.com/role/ScheduleOfReconciliationFromAggregatePrincipalAmountOf6.50ConvertibleNotesDue2029Details" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#DebtCapitalActivitiesDetailsNarrative" roleURI="http://surocap.com/role/DebtCapitalActivitiesDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfEquityIncentivePlanDetails" roleURI="http://surocap.com/role/ScheduleOfEquityIncentivePlanDetails" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#Stock-basedCompensationDetailsNarrative" roleURI="http://surocap.com/role/Stock-basedCompensationDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfInvestmentsByCompanyDetails" roleURI="http://surocap.com/role/ScheduleOfInvestmentsByCompanyDetails" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfInvestmentsByCompanyDetailsParenthetical" roleURI="http://surocap.com/role/ScheduleOfInvestmentsByCompanyDetailsParenthetical" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfInvestmentsDetails" roleURI="http://surocap.com/role/ScheduleOfInvestmentsDetails" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfInvestmentsDetailsParenthetical" roleURI="http://surocap.com/role/ScheduleOfInvestmentsDetailsParenthetical" />
    <link:roleRef xlink:type="simple" xlink:href="ssss-20251231.xsd#ScheduleOfQuarterlyFinancialDataDetails" roleURI="http://surocap.com/role/ScheduleOfQuarterlyFinancialDataDetails" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/Cover" xlink:title="00000001 - Document - Cover" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/StatementsOfAssetsAndLiabilities" xlink:title="00000002 - Statement - Consolidated Statements of Assets and Liabilities">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Assets" xlink:label="loc_us-gaapAssets" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InvestmentOwnedAtFairValue" xlink:label="loc_us-gaapInvestmentOwnedAtFairValue" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssets" xlink:to="loc_us-gaapInvestmentOwnedAtFairValue" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Cash" xlink:label="loc_us-gaapCash" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssets" xlink:to="loc_us-gaapCash" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedCashCurrent" xlink:label="loc_us-gaapRestrictedCashCurrent" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssets" xlink:to="loc_us-gaapRestrictedCashCurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="ssss-20251231.xsd#SSSS_EscrowProceedsReceivable" xlink:label="loc_SSSSEscrowProceedsReceivable" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssets" xlink:to="loc_SSSSEscrowProceedsReceivable" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="ssss-20251231.xsd#SSSS_InterestAndDividendsReceivable" xlink:label="loc_SSSSInterestAndDividendsReceivable" />
      <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssets" xlink:to="loc_SSSSInterestAndDividendsReceivable" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredCostsCurrentAndNoncurrent" xlink:label="loc_us-gaapDeferredCostsCurrentAndNoncurrent" />
      <link:calculationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssets" xlink:to="loc_us-gaapDeferredCostsCurrentAndNoncurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PrepaidExpenseAndOtherAssets" xlink:label="loc_us-gaapPrepaidExpenseAndOtherAssets" />
      <link:calculationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssets" xlink:to="loc_us-gaapPrepaidExpenseAndOtherAssets" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaapLiabilities" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NotesPayable" xlink:label="loc_us-gaapNotesPayable" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilities" xlink:to="loc_us-gaapNotesPayable" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="ssss-20251231.xsd#SSSS_ConvertibleNotes" xlink:label="loc_SSSSConvertibleNotes" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilities" xlink:to="loc_SSSSConvertibleNotes" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent" xlink:label="loc_us-gaapAccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilities" xlink:to="loc_us-gaapAccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DividendsPayableCurrentAndNoncurrent" xlink:label="loc_us-gaapDividendsPayableCurrentAndNoncurrent" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilities" xlink:to="loc_us-gaapDividendsPayableCurrentAndNoncurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsNet" xlink:label="loc_us-gaapAssetsNet" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssetsNet" xlink:to="loc_us-gaapAssets" xlink:type="arc" weight="1" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssetsNet" xlink:to="loc_us-gaapLiabilities" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaapStockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockValue" xlink:label="loc_us-gaapCommonStockValue" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapStockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:to="loc_us-gaapCommonStockValue" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdditionalPaidInCapital" xlink:label="loc_us-gaapAdditionalPaidInCapital" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapStockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:to="loc_us-gaapAdditionalPaidInCapital" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="ssss-20251231.xsd#SSSS_AccumulatedNetInvestmentLoss" xlink:label="loc_SSSSAccumulatedNetInvestmentLoss" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapStockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:to="loc_SSSSAccumulatedNetInvestmentLoss" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="ssss-20251231.xsd#SSSS_AccumulatedNetRealizedGainOnInvestmentsNetOfDistributions" xlink:label="loc_SSSSAccumulatedNetRealizedGainOnInvestmentsNetOfDistributions" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapStockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:to="loc_SSSSAccumulatedNetRealizedGainOnInvestmentsNetOfDistributions" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="ssss-20251231.xsd#SSSS_AccumulatedNetUnrealizedDepreciationAppreciationOfInvestments" xlink:label="loc_SSSSAccumulatedNetUnrealizedDepreciationAppreciationOfInvestments" />
      <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapStockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:to="loc_SSSSAccumulatedNetUnrealizedDepreciationAppreciationOfInvestments" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/StatementsOfAssetsAndLiabilitiesParenthetical" xlink:title="00000003 - Statement - Consolidated Statements of Assets and Liabilities (Parenthetical)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/StatementsOfOperations" xlink:title="00000004 - Statement - Consolidated Statements of Operations">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InvestmentIncomeInterestAndDividend" xlink:label="loc_us-gaapInvestmentIncomeInterestAndDividend" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InvestmentIncomeInterest" xlink:label="loc_us-gaapInvestmentIncomeInterest" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapInvestmentIncomeInterestAndDividend" xlink:to="loc_us-gaapInvestmentIncomeInterest" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InvestmentIncomeDividend" xlink:label="loc_us-gaapInvestmentIncomeDividend" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapInvestmentIncomeInterestAndDividend" xlink:to="loc_us-gaapInvestmentIncomeDividend" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestIncomeSecuritiesUSTreasury" xlink:label="loc_us-gaapInterestIncomeSecuritiesUSTreasury" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapInvestmentIncomeInterestAndDividend" xlink:to="loc_us-gaapInterestIncomeSecuritiesUSTreasury" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingExpenses" xlink:label="loc_us-gaapOperatingExpenses" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CompensationExpenseExcludingCostOfGoodAndServiceSold" xlink:label="loc_us-gaapCompensationExpenseExcludingCostOfGoodAndServiceSold" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOperatingExpenses" xlink:to="loc_us-gaapCompensationExpenseExcludingCostOfGoodAndServiceSold" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="ssss-20251231.xsd#SSSS_DirectorsFees" xlink:label="loc_SSSSDirectorsFees" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOperatingExpenses" xlink:to="loc_SSSSDirectorsFees" xlink:type="arc" 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="loc_us-gaapInterestExpenseOperating" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOperatingExpenses" xlink:to="loc_us-gaapInterestExpenseOperating" xlink:type="arc" 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="loc_us-gaapProfessionalFees" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOperatingExpenses" xlink:to="loc_us-gaapProfessionalFees" xlink:type="arc" 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="loc_us-gaapIncomeTaxExpenseBenefit" />
      <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOperatingExpenses" xlink:to="loc_us-gaapIncomeTaxExpenseBenefit" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherExpenses" xlink:label="loc_us-gaapOtherExpenses" />
      <link:calculationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOperatingExpenses" xlink:to="loc_us-gaapOtherExpenses" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetInvestmentIncome" xlink:label="loc_us-gaapNetInvestmentIncome" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetInvestmentIncome" xlink:to="loc_us-gaapInvestmentIncomeInterestAndDividend" xlink:type="arc" weight="1" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetInvestmentIncome" xlink:to="loc_us-gaapOperatingExpenses" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaapNetIncomeLoss" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetIncomeLoss" xlink:to="loc_us-gaapNetInvestmentIncome" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealizedInvestmentGainsLosses" xlink:label="loc_us-gaapRealizedInvestmentGainsLosses" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetIncomeLoss" xlink:to="loc_us-gaapRealizedInvestmentGainsLosses" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="ssss-20251231.xsd#SSSS_RealizedInvestmentGainsLossesRepurchase" xlink:label="loc_SSSSRealizedInvestmentGainsLossesRepurchase" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetIncomeLoss" xlink:to="loc_SSSSRealizedInvestmentGainsLossesRepurchase" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_UnrealizedGainLossOnInvestments" xlink:label="loc_us-gaapUnrealizedGainLossOnInvestments" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetIncomeLoss" xlink:to="loc_us-gaapUnrealizedGainLossOnInvestments" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/StatementsOfOperationsParenthetical" xlink:title="00000005 - Statement - Consolidated Statements of Operations (Parenthetical)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/StatementsOfChangesInNetAssets" xlink:title="00000006 - Statement - Consolidated Statements of Changes in Net Assets" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/StatementsOfCashFlows" xlink:title="00000007 - 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_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaapNetIncomeLoss" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapNetIncomeLoss" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="ssss-20251231.xsd#SSSS_RealizedInvestmentGainLosses" xlink:label="loc_SSSSRealizedInvestmentGainLosses" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_SSSSRealizedInvestmentGainLosses" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_UnrealizedGainLossOnInvestments" xlink:label="loc_us-gaapUnrealizedGainLossOnInvestments" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapUnrealizedGainLossOnInvestments" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensation" xlink:label="loc_us-gaapShareBasedCompensation" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapShareBasedCompensation" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AmortizationOfDebtDiscountPremium" xlink:label="loc_us-gaapAmortizationOfDebtDiscountPremium" />
      <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapAmortizationOfDebtDiscountPremium" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="ssss-20251231.xsd#SSSS_AmortizationOfConvertibleSeniorDebtDiscount" xlink:label="loc_SSSSAmortizationOfConvertibleSeniorDebtDiscount" />
      <link:calculationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_SSSSAmortizationOfConvertibleSeniorDebtDiscount" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="ssss-20251231.xsd#SSSS_AdjustmentsToEscrowProceedsReceivable" xlink:label="loc_SSSSAdjustmentsToEscrowProceedsReceivable" />
      <link:calculationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_SSSSAdjustmentsToEscrowProceedsReceivable" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="ssss-20251231.xsd#SSSS_AccruedInterestOnUSTreasuryBills" xlink:label="loc_SSSSAccruedInterestOnUSTreasuryBills" />
      <link:calculationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_SSSSAccruedInterestOnUSTreasuryBills" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="ssss-20251231.xsd#SSSS_PurchasesOfPortfolioInvestments" xlink:label="loc_SSSSPurchasesOfPortfolioInvestments" />
      <link:calculationArc order="9" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_SSSSPurchasesOfPortfolioInvestments" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="ssss-20251231.xsd#SSSS_PurchasesOfUSTreasuryBillsInvestments" xlink:label="loc_SSSSPurchasesOfUSTreasuryBillsInvestments" />
      <link:calculationArc order="10" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_SSSSPurchasesOfUSTreasuryBillsInvestments" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="ssss-20251231.xsd#SSSS_ProceedsFromSalesOrMaturityOfInvestmentsPortfolioInvestments" xlink:label="loc_SSSSProceedsFromSalesOrMaturityOfInvestmentsPortfolioInvestments" />
      <link:calculationArc order="11" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_SSSSProceedsFromSalesOrMaturityOfInvestmentsPortfolioInvestments" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="ssss-20251231.xsd#SSSS_ProceedsFromSalesOrMaturityOfInvestmentsUSTreasuryBills" xlink:label="loc_SSSSProceedsFromSalesOrMaturityOfInvestmentsUSTreasuryBills" />
      <link:calculationArc order="12" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_SSSSProceedsFromSalesOrMaturityOfInvestmentsUSTreasuryBills" xlink:type="arc" 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="loc_us-gaapIncreaseDecreaseInAccountsPayableAndAccruedLiabilities" />
      <link:calculationArc order="13" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapIncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInInterestAndDividendsReceivable" xlink:label="loc_us-gaapIncreaseDecreaseInInterestAndDividendsReceivable" />
      <link:calculationArc order="14" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapIncreaseDecreaseInInterestAndDividendsReceivable" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="ssss-20251231.xsd#SSSS_IncreaseDecreaseInEscrowProceedsReceivable" xlink:label="loc_SSSSIncreaseDecreaseInEscrowProceedsReceivable" />
      <link:calculationArc order="15" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_SSSSIncreaseDecreaseInEscrowProceedsReceivable" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:label="loc_us-gaapIncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" />
      <link:calculationArc order="16" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapIncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:type="arc" 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="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:label="loc_us-gaapProceedsFromIssuanceOfCommonStock" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaapProceedsFromIssuanceOfCommonStock" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromConvertibleDebt" xlink:label="loc_us-gaapProceedsFromConvertibleDebt" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaapProceedsFromConvertibleDebt" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="ssss-20251231.xsd#SSSS_PaymentsOfDeferredDebtIssuanceCosts" xlink:label="loc_SSSSPaymentsOfDeferredDebtIssuanceCosts" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_SSSSPaymentsOfDeferredDebtIssuanceCosts" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="ssss-20251231.xsd#SSSS_PaymentsForRepurchaseOfNotes" xlink:label="loc_SSSSPaymentsForRepurchaseOfNotes" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_SSSSPaymentsForRepurchaseOfNotes" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="ssss-20251231.xsd#SSSS_PaymentsForRepurchaseOnPartialRepurchase" xlink:label="loc_SSSSPaymentsForRepurchaseOnPartialRepurchase" />
      <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_SSSSPaymentsForRepurchaseOnPartialRepurchase" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsForRepurchaseOfCommonStock" xlink:label="loc_us-gaapPaymentsForRepurchaseOfCommonStock" />
      <link:calculationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaapPaymentsForRepurchaseOfCommonStock" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsOfFinancingCosts" xlink:label="loc_us-gaapPaymentsOfFinancingCosts" />
      <link:calculationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaapPaymentsOfFinancingCosts" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsOfDividends" xlink:label="loc_us-gaapPaymentsOfDividends" />
      <link:calculationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaapPaymentsOfDividends" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:label="loc_us-gaapCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:to="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:type="arc" weight="1" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:to="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/StatementsOfCashFlowsParenthetical" xlink:title="00000008 - Statement - Consolidated Statements of Cash Flows (Parenthetical)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfInvestments" xlink:title="00000009 - Statement - Consolidated Schedule of Investments" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfInvestmentsParenthetical" xlink:title="00000010 - Statement - Condensed Consolidated Schedule of Investments (Unaudited) (Parenthetical)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure" xlink:title="00000016 - Disclosure - Cybersecurity Risk Management and Strategy Disclosure" />
    <link:calculationLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/cyd/role/MaterialCybersecurityIncidentDisclosure" xlink:title="00000017 - Disclosure - Material Cybersecurity Incident Disclosure" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/NatureOfOperations" xlink:title="999018 - Disclosure - NATURE OF OPERATIONS" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/SignificantAccountingPolicies" xlink:title="999019 - Disclosure - SIGNIFICANT ACCOUNTING POLICIES" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/Related-partyArrangements" xlink:title="999020 - Disclosure - RELATED-PARTY ARRANGEMENTS" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/InvestmentsAtFairValue" xlink:title="999021 - Disclosure - INVESTMENTS AT FAIR VALUE" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/CommonStock" xlink:title="999022 - Disclosure - COMMON STOCK" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/NetChangeInNetAssetsResultingFromOperationsPerCommonSharebasicAndDiluted" xlink:title="999023 - Disclosure - NET CHANGE IN NET ASSETS RESULTING FROM OPERATIONS PER COMMON SHARE&#8212;BASIC AND DILUTED" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/CommitmentsAndContingencies" xlink:title="999024 - Disclosure - COMMITMENTS AND CONTINGENCIES" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/FinancialHighlights" xlink:title="999025 - Disclosure - FINANCIAL HIGHLIGHTS" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/IncomeTaxes" xlink:title="999026 - Disclosure - INCOME TAXES" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/DebtCapitalActivities" xlink:title="999027 - Disclosure - DEBT CAPITAL ACTIVITIES" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/Stock-basedCompensation" xlink:title="999028 - Disclosure - STOCK-BASED COMPENSATION" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/SubsequentEvents" xlink:title="999029 - Disclosure - SUBSEQUENT EVENTS" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/SelectedQuarterlyFinancialData" xlink:title="999030 - Disclosure - SELECTED QUARTERLY FINANCIAL DATA" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/SupplementalFinancialData" xlink:title="999031 - Disclosure - SUPPLEMENTAL FINANCIAL DATA" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/SignificantAccountingPoliciesPolicies" xlink:title="999032 - Disclosure - SIGNIFICANT ACCOUNTING POLICIES (Policies)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/NatureOfOperationsTables" xlink:title="999033 - Disclosure - NATURE OF OPERATIONS (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/SignificantAccountingPoliciesTables" xlink:title="999034 - Disclosure - SIGNIFICANT ACCOUNTING POLICIES (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/InvestmentsAtFairValueTables" xlink:title="999035 - Disclosure - INVESTMENTS AT FAIR VALUE (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/CommonStockTables" xlink:title="999036 - Disclosure - COMMON STOCK (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/NetChangeInNetAssetsResultingFromOperationsPerCommonSharebasicAndDilutedTables" xlink:title="999037 - Disclosure - NET CHANGE IN NET ASSETS RESULTING FROM OPERATIONS PER COMMON SHARE&#8212;BASIC AND DILUTED (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/CommitmentsAndContingenciesTables" xlink:title="999038 - Disclosure - COMMITMENTS AND CONTINGENCIES (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/FinancialHighlightsTables" xlink:title="999039 - Disclosure - FINANCIAL HIGHLIGHTS (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/IncomeTaxesTables" xlink:title="999040 - Disclosure - INCOME TAXES (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/DebtCapitalActivitiesTables" xlink:title="999041 - Disclosure - DEBT CAPITAL ACTIVITIES (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/Stock-basedCompensationTables" xlink:title="999042 - Disclosure - STOCK-BASED COMPENSATION (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/SubsequentEventsTables" xlink:title="999043 - Disclosure - SUBSEQUENT EVENTS (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/SelectedQuarterlyFinancialDataTables" xlink:title="999044 - Disclosure - SELECTED QUARTERLY FINANCIAL DATA (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfCompanysSubsidiariesDetails" xlink:title="999045 - Disclosure - SCHEDULE OF COMPANY&#8217;S SUBSIDIARIES (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfDeferredFinancingCostsDetails" xlink:title="999046 - Disclosure - SCHEDULE OF DEFERRED FINANCING COSTS (Details)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredFinanceCostsNet" xlink:label="loc_us-gaapDeferredFinanceCostsNet" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredFinanceCostsGross" xlink:label="loc_us-gaapDeferredFinanceCostsGross" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapDeferredFinanceCostsNet" xlink:to="loc_us-gaapDeferredFinanceCostsGross" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredCostsCurrentAndNoncurrent" xlink:label="loc_us-gaapDeferredCostsCurrentAndNoncurrent" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapDeferredFinanceCostsNet" xlink:to="loc_us-gaapDeferredCostsCurrentAndNoncurrent" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/SignificantAccountingPoliciesDetailsNarrative" xlink:title="999047 - Disclosure - SIGNIFICANT ACCOUNTING POLICIES (Details Narrative)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/Related-partyArrangementsDetailsNarrative" xlink:title="999048 - Disclosure - RELATED-PARTY ARRANGEMENTS (Details Narrative)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfCompositionOfInvestmentPortfolioDetails" xlink:title="999049 - Disclosure - SCHEDULE OF COMPOSITION OF INVESTMENT PORTFOLIO (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfFairValueOfInvestmentValuationInputsDetails" xlink:title="999050 - Disclosure - SCHEDULE OF FAIR VALUE OF INVESTMENT VALUATION INPUTS (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfFairValueOfAssetsOnUnobservableInputDetails" xlink:title="999051 - Disclosure - SCHEDULE OF FAIR VALUE OF ASSETS ON UNOBSERVABLE INPUT (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfAggregateValueOfAssetsAndLiabilitiesDetails" xlink:title="999052 - Disclosure - SCHEDULE OF AGGREGATE VALUE OF ASSETS AND LIABILITIES (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfAggregateValueOfAssetsAndLiabilitiesDetailsParenthetical" xlink:title="999053 - Disclosure - SCHEDULE OF AGGREGATE VALUE OF ASSETS AND LIABILITIES (Details) (Parenthetical)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfInvestmentsInAndAdvancesToAffiliatesDetails" xlink:title="999054 - Disclosure - SCHEDULE OF INVESTMENTS IN AND ADVANCES TO AFFILIATES (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfInvestmentsInAndAdvancesToAffiliatesDetailsParenthetical" xlink:title="999055 - Disclosure - SCHEDULE OF INVESTMENTS IN AND ADVANCES TO AFFILIATES (Details) (Parenthetical)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/InvestmentsAtFairValueDetailsNarrative" xlink:title="999056 - Disclosure - INVESTMENTS AT FAIR VALUE (Details Narrative)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfSharesSoldUnderAtmProgramDetails" xlink:title="999057 - Disclosure - SCHEDULE OF SHARES SOLD UNDER ATM PROGRAM (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/CommonStockDetailsNarrative" xlink:title="999058 - Disclosure - COMMON STOCK (Details Narrative)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfBasicAndDilutedCommonShareDetails" xlink:title="999059 - Disclosure - SCHEDULE OF BASIC AND DILUTED COMMON SHARE (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfBasicAndDilutedCommonShareDetailsParenthetical" xlink:title="999060 - Disclosure - SCHEDULE OF BASIC AND DILUTED COMMON SHARE (Details) (Parenthetical)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfFutureMinimumPaymentsOfOperationLeaseDetails" xlink:title="999061 - Disclosure - SCHEDULE OF FUTURE MINIMUM PAYMENTS OF OPERATION LEASE (Details)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:label="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDue" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:label="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:label="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDueYearTwo" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:label="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDueYearThree" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/CommitmentsAndContingenciesDetailsNarrative" xlink:title="999062 - Disclosure - COMMITMENTS AND CONTINGENCIES (Details Narrative)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfFinancialHighlightsDetails" xlink:title="999063 - Disclosure - SCHEDULE OF FINANCIAL HIGHLIGHTS (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfFinancialHighlightsDetailsParenthetical" xlink:title="999064 - Disclosure - SCHEDULE OF FINANCIAL HIGHLIGHTS (Details) (Parenthetical)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfEffectiveIncomeTaxRateReconciliationDetails" xlink:title="999065 - Disclosure - SCHEDULE OF EFFECTIVE INCOME TAX RATE RECONCILIATION (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="loc_us-gaapIncomeTaxExpenseBenefit" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate" xlink:label="loc_us-gaapIncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapIncomeTaxExpenseBenefit" xlink:to="loc_us-gaapIncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="ssss-20251231.xsd#SSSS_IncomeTaxReconciliationDividendsPaidDeductionRICQualification" xlink:label="loc_SSSSIncomeTaxReconciliationDividendsPaidDeductionRICQualification" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapIncomeTaxExpenseBenefit" xlink:to="loc_SSSSIncomeTaxReconciliationDividendsPaidDeductionRICQualification" xlink:type="arc" 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="loc_us-gaapIncomeTaxReconciliationStateAndLocalIncomeTaxes" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapIncomeTaxExpenseBenefit" xlink:to="loc_us-gaapIncomeTaxReconciliationStateAndLocalIncomeTaxes" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="ssss-20251231.xsd#SSSS_IncomeTaxReconciliationBlockerCorporationIncomeTaxesRrefund" xlink:label="loc_SSSSIncomeTaxReconciliationBlockerCorporationIncomeTaxesRrefund" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapIncomeTaxExpenseBenefit" xlink:to="loc_SSSSIncomeTaxReconciliationBlockerCorporationIncomeTaxesRrefund" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxReconciliationOtherReconcilingItems" xlink:label="loc_us-gaapIncomeTaxReconciliationOtherReconcilingItems" />
      <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapIncomeTaxExpenseBenefit" xlink:to="loc_us-gaapIncomeTaxReconciliationOtherReconcilingItems" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:label="loc_us-gaapEffectiveIncomeTaxRateContinuingOperations" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:label="loc_us-gaapEffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapEffectiveIncomeTaxRateContinuingOperations" xlink:to="loc_us-gaapEffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="ssss-20251231.xsd#SSSS_EffectiveIncomeTaxRateReconciliationDividendsPaidDeductionRICQualificationRate" xlink:label="loc_SSSSEffectiveIncomeTaxRateReconciliationDividendsPaidDeductionRICQualificationRate" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapEffectiveIncomeTaxRateContinuingOperations" xlink:to="loc_SSSSEffectiveIncomeTaxRateReconciliationDividendsPaidDeductionRICQualificationRate" xlink:type="arc" 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="loc_us-gaapEffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapEffectiveIncomeTaxRateContinuingOperations" xlink:to="loc_us-gaapEffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="ssss-20251231.xsd#SSSS_IncomeTaxReconciliationBlockerCorporationIncomeTaxesRrefundRate" xlink:label="loc_SSSSIncomeTaxReconciliationBlockerCorporationIncomeTaxesRrefundRate" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapEffectiveIncomeTaxRateContinuingOperations" xlink:to="loc_SSSSIncomeTaxReconciliationBlockerCorporationIncomeTaxesRrefundRate" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercent" xlink:label="loc_us-gaapEffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercent" />
      <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapEffectiveIncomeTaxRateContinuingOperations" xlink:to="loc_us-gaapEffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercent" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfFederalIncomeTaxDetails" xlink:title="999066 - Disclosure - SCHEDULE OF FEDERAL INCOME TAX (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfAggregateIncomeTaxDetails" xlink:title="999067 - Disclosure - SCHEDULE OF AGGREGATE INCOME TAX (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfProvisionForIncomeTaxesDetails" xlink:title="999068 - Disclosure - SCHEDULE OF PROVISION FOR INCOME TAXES (Details)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FederalStateAndLocalIncomeTaxExpenseBenefitContinuingOperations" xlink:label="loc_us-gaapFederalStateAndLocalIncomeTaxExpenseBenefitContinuingOperations" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CurrentFederalTaxExpenseBenefit" xlink:label="loc_us-gaapCurrentFederalTaxExpenseBenefit" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapFederalStateAndLocalIncomeTaxExpenseBenefitContinuingOperations" xlink:to="loc_us-gaapCurrentFederalTaxExpenseBenefit" xlink:type="arc" 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="loc_us-gaapDeferredFederalIncomeTaxExpenseBenefit" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapFederalStateAndLocalIncomeTaxExpenseBenefitContinuingOperations" xlink:to="loc_us-gaapDeferredFederalIncomeTaxExpenseBenefit" xlink:type="arc" 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="loc_us-gaapCurrentStateAndLocalTaxExpenseBenefit" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapFederalStateAndLocalIncomeTaxExpenseBenefitContinuingOperations" xlink:to="loc_us-gaapCurrentStateAndLocalTaxExpenseBenefit" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfReclassificationOfBooktaxDifferencesDetails" xlink:title="999069 - Disclosure - SCHEDULE OF RECLASSIFICATION OF BOOK/TAX DIFFERENCES (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfTaxCharacterOfDistributionsDetails" xlink:title="999070 - Disclosure - SCHEDULE OF TAX CHARACTER OF DISTRIBUTIONS (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfComponentsOfDistributedEarningsOnTaxBasisDetails" xlink:title="999071 - Disclosure - SCHEDULE OF COMPONENTS OF DISTRIBUTED EARNINGS ON A TAX BASIS (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/IncomeTaxesDetailsNarrative" xlink:title="999072 - Disclosure - INCOME TAXES (Details Narrative)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfReconciliationFromAggregatePrincipalAmountOf6.00NotesDue2026Details" xlink:title="999073 - Disclosure - SCHEDULE OF RECONCILIATION FROM AGGREGATE PRINCIPAL AMOUNT OF 6.00% NOTES DUE 2026 (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfReconciliationFromAggregatePrincipalAmountOf6.50ConvertibleNotesDue2029Details" xlink:title="999074 - Disclosure - SCHEDULE OF RECONCILIATION FROM AGGREGATE PRINCIPAL AMOUNT OF 6.50% CONVERTIBLE NOTES DUE 2029 (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/DebtCapitalActivitiesDetailsNarrative" xlink:title="999075 - Disclosure - DEBT CAPITAL ACTIVITIES (Details Narrative)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfEquityIncentivePlanDetails" xlink:title="999076 - Disclosure - SCHEDULE OF EQUITY INCENTIVE PLAN (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/Stock-basedCompensationDetailsNarrative" xlink:title="999077 - Disclosure - STOCK-BASED COMPENSATION (Details Narrative)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfInvestmentsByCompanyDetails" xlink:title="999078 - Disclosure - SCHEDULE OF INVESTMENTS BY COMPANY (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfInvestmentsByCompanyDetailsParenthetical" xlink:title="999079 - Disclosure - SCHEDULE OF INVESTMENTS BY COMPANY (Details) (Parenthetical)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfInvestmentsDetails" xlink:title="999080 - Disclosure - SCHEDULE OF INVESTMENTS (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfInvestmentsDetailsParenthetical" xlink:title="999081 - Disclosure - SCHEDULE OF INVESTMENTS (Details) (Parenthetical)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://surocap.com/role/ScheduleOfQuarterlyFinancialDataDetails" xlink:title="999082 - Disclosure - SCHEDULE OF QUARTERLY FINANCIAL DATA (Details)" />
</link:linkbase>
