<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019e69f8-2d81-77ca-8903-39e54c0aaf56,g:1d959164-9ea0-4c26-bfbb-8041dd74d633-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" 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">
  <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:roleRef roleURI="http://www.unionbankvt.com/role/CONSOLIDATEDBALANCESHEETS" xlink:type="simple" xlink:href="unb-20260630.xsd#CONSOLIDATEDBALANCESHEETS"/>
  <link:calculationLink xlink:role="http://www.unionbankvt.com/role/CONSOLIDATEDBALANCESHEETS" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_019e69f8-3111-70dd-a931-d6c792f6e35a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Liabilities"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Deposits_019e69f8-3111-75f8-8689-444e708b3fb4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Deposits"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_019e69f8-3111-70dd-a931-d6c792f6e35a" xlink:to="loc_us-gaap_Deposits_019e69f8-3111-75f8-8689-444e708b3fb4" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_unb_AdvanceFromFederalHomeLoanBankAndFederalReserveBank_019e69f8-3111-75bd-ad97-5d6f10f1bb53" xlink:href="unb-20260630.xsd#unb_AdvanceFromFederalHomeLoanBankAndFederalReserveBank"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_019e69f8-3111-70dd-a931-d6c792f6e35a" xlink:to="loc_unb_AdvanceFromFederalHomeLoanBankAndFederalReserveBank_019e69f8-3111-75bd-ad97-5d6f10f1bb53" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubordinatedDebt_019e69f8-3111-769e-ac1d-8d04e5308164" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubordinatedDebt"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_019e69f8-3111-70dd-a931-d6c792f6e35a" xlink:to="loc_us-gaap_SubordinatedDebt_019e69f8-3111-769e-ac1d-8d04e5308164" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilities_019e69f8-3111-7b14-ba63-9eaf08e5c7b4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilities"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_019e69f8-3111-70dd-a931-d6c792f6e35a" xlink:to="loc_us-gaap_OtherLiabilities_019e69f8-3111-7b14-ba63-9eaf08e5c7b4" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Investments_019fa676-7457-716f-bec1-256dcc06a439" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Investments"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_019fa676-7457-72ab-a306-100d2ae482de" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Investments_019fa676-7457-716f-bec1-256dcc06a439" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_019fa676-7457-72ab-a306-100d2ae482de" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherInvestments_019fa676-7457-74f9-a64e-6c7a98b96528" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherInvestments"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Investments_019fa676-7457-716f-bec1-256dcc06a439" xlink:to="loc_us-gaap_OtherInvestments_019fa676-7457-74f9-a64e-6c7a98b96528" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e69f8-3111-7f0a-80bf-0abd5eda740e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue_019e69f8-3111-76df-a7bf-6e8f7f35262a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockValue"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_019e69f8-3111-7f0a-80bf-0abd5eda740e" xlink:to="loc_us-gaap_CommonStockValue_019e69f8-3111-76df-a7bf-6e8f7f35262a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapital_019e69f8-3111-7b03-9dc4-f7abd86633e6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapital"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_019e69f8-3111-7f0a-80bf-0abd5eda740e" xlink:to="loc_us-gaap_AdditionalPaidInCapital_019e69f8-3111-7b03-9dc4-f7abd86633e6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_019e69f8-3111-7b2b-96dc-1b483ad09c88" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_019e69f8-3111-7f0a-80bf-0abd5eda740e" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_019e69f8-3111-7b2b-96dc-1b483ad09c88" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonValue_019e69f8-3111-7626-b57f-266ddf7d8b3e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockCommonValue"/>
    <link:calculationArc order="4" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_019e69f8-3111-7f0a-80bf-0abd5eda740e" xlink:to="loc_us-gaap_TreasuryStockCommonValue_019e69f8-3111-7626-b57f-266ddf7d8b3e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_019e69f8-3111-7312-8593-81310d01aab4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_019e69f8-3111-7f0a-80bf-0abd5eda740e" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_019e69f8-3111-7312-8593-81310d01aab4" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_019e69f8-3111-7ecf-b360-77f6f1cf5b16" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_019e69f8-3111-7108-b38e-b8246cb8ec48" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Liabilities"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_019e69f8-3111-7ecf-b360-77f6f1cf5b16" xlink:to="loc_us-gaap_Liabilities_019e69f8-3111-7108-b38e-b8246cb8ec48" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingencies_019e69f8-3111-71ec-8ed4-090c72e3fce8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommitmentsAndContingencies"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_019e69f8-3111-7ecf-b360-77f6f1cf5b16" xlink:to="loc_us-gaap_CommitmentsAndContingencies_019e69f8-3111-71ec-8ed4-090c72e3fce8" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e69f8-3111-7be3-97b8-f5e075602dc3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_019e69f8-3111-7ecf-b360-77f6f1cf5b16" xlink:to="loc_us-gaap_StockholdersEquity_019e69f8-3111-7be3-97b8-f5e075602dc3" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_019e69f8-3111-7b57-81c0-5b9d4c4ea5c6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Assets"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019e69f8-3111-7309-a31e-e12b2e2c04e9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019e69f8-3111-7b57-81c0-5b9d4c4ea5c6" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019e69f8-3111-7309-a31e-e12b2e2c04e9" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_unb_InvestmentInInterestBearingDepositsInBanks_019e69f8-3111-7d88-94d4-d34c2017e9e8" xlink:href="unb-20260630.xsd#unb_InvestmentInInterestBearingDepositsInBanks"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019e69f8-3111-7b57-81c0-5b9d4c4ea5c6" xlink:to="loc_unb_InvestmentInInterestBearingDepositsInBanks_019e69f8-3111-7d88-94d4-d34c2017e9e8" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Investments_019e69f8-3111-71eb-9acc-0cf29b80fc37" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Investments"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019e69f8-3111-7b57-81c0-5b9d4c4ea5c6" xlink:to="loc_us-gaap_Investments_019e69f8-3111-71eb-9acc-0cf29b80fc37" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansReceivableHeldForSaleNetNotPartOfDisposalGroup_019e69f8-3111-7773-ab12-dd654a4f30f2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LoansReceivableHeldForSaleNetNotPartOfDisposalGroup"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019e69f8-3111-7b57-81c0-5b9d4c4ea5c6" xlink:to="loc_us-gaap_LoansReceivableHeldForSaleNetNotPartOfDisposalGroup_019e69f8-3111-7773-ab12-dd654a4f30f2" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss_019e69f8-3111-7526-a6e6-609bff1f5704" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019e69f8-3111-7b57-81c0-5b9d4c4ea5c6" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss_019e69f8-3111-7526-a6e6-609bff1f5704" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_019e69f8-3111-7dab-9293-d02d5551e10e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019e69f8-3111-7b57-81c0-5b9d4c4ea5c6" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_019e69f8-3111-7dab-9293-d02d5551e10e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssets_019e69f8-3111-7077-94c7-3a3278e5b313" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssets"/>
    <link:calculationArc order="7" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019e69f8-3111-7b57-81c0-5b9d4c4ea5c6" xlink:to="loc_us-gaap_OtherAssets_019e69f8-3111-7077-94c7-3a3278e5b313" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019e69f8-3111-7d80-b010-c57651f933b7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndDueFromBanks_019e69f8-3111-73de-836e-e9246ccb2536" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndDueFromBanks"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019e69f8-3111-7d80-b010-c57651f933b7" xlink:to="loc_us-gaap_CashAndDueFromBanks_019e69f8-3111-73de-836e-e9246ccb2536" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalFundsSold_019e69f8-3111-7490-8375-d0125853c8e5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FederalFundsSold"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019e69f8-3111-7d80-b010-c57651f933b7" xlink:to="loc_us-gaap_FederalFundsSold_019e69f8-3111-7490-8375-d0125853c8e5" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Deposits_019e69f8-3111-744b-8e73-767786ae7d60" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Deposits"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestBearingDepositLiabilities_019e69f8-3111-7aaa-a75c-a22cd0f47baa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoninterestBearingDepositLiabilities"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Deposits_019e69f8-3111-744b-8e73-767786ae7d60" xlink:to="loc_us-gaap_NoninterestBearingDepositLiabilities_019e69f8-3111-7aaa-a75c-a22cd0f47baa" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_unb_InterestBearingNonTimeDeposits_019e69f8-3111-7f63-8ca0-8aa5b9a3e400" xlink:href="unb-20260630.xsd#unb_InterestBearingNonTimeDeposits"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Deposits_019e69f8-3111-744b-8e73-767786ae7d60" xlink:to="loc_unb_InterestBearingNonTimeDeposits_019e69f8-3111-7f63-8ca0-8aa5b9a3e400" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimeDeposits_019e69f8-3111-77b8-a580-a6440edfc423" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TimeDeposits"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Deposits_019e69f8-3111-744b-8e73-767786ae7d60" xlink:to="loc_us-gaap_TimeDeposits_019e69f8-3111-77b8-a580-a6440edfc423" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.unionbankvt.com/role/CONSOLIDATEDSTATEMENTSOFINCOMEUnaudited" xlink:type="simple" xlink:href="unb-20260630.xsd#CONSOLIDATEDSTATEMENTSOFINCOMEUnaudited"/>
  <link:calculationLink xlink:role="http://www.unionbankvt.com/role/CONSOLIDATEDSTATEMENTSOFINCOMEUnaudited" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseOperating_019e69f8-3111-749f-a43d-f2e176342795" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseOperating"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseDeposits_019e69f8-3111-776c-865c-8fc9a9d1ecd2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseDeposits"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_InterestExpenseOperating_019e69f8-3111-749f-a43d-f2e176342795" xlink:to="loc_us-gaap_InterestExpenseDeposits_019e69f8-3111-776c-865c-8fc9a9d1ecd2" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesShortTerm_019e69f8-3111-7b0a-a254-8bf193aadbe9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesShortTerm"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_InterestExpenseOperating_019e69f8-3111-749f-a43d-f2e176342795" xlink:to="loc_us-gaap_InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesShortTerm_019e69f8-3111-7b0a-a254-8bf193aadbe9" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseSubordinatedNotesAndDebentures_019e69f8-3111-7192-8809-ff037a14437b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseSubordinatedNotesAndDebentures"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_InterestExpenseOperating_019e69f8-3111-749f-a43d-f2e176342795" xlink:to="loc_us-gaap_InterestExpenseSubordinatedNotesAndDebentures_019e69f8-3111-7192-8809-ff037a14437b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019e69f8-3111-7a06-8b76-a4e6219f8957" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossAttributableToParent_019e69f8-3111-738a-942e-cfadbff5013e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossAttributableToParent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss_019e69f8-3111-7a06-8b76-a4e6219f8957" xlink:to="loc_us-gaap_IncomeLossAttributableToParent_019e69f8-3111-738a-942e-cfadbff5013e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_019e69f8-3111-76cd-b3aa-2f51b4a2c20e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss_019e69f8-3111-7a06-8b76-a4e6219f8957" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_019e69f8-3111-76cd-b3aa-2f51b4a2c20e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss_019e69f8-3111-7132-b49b-49c457b2ce57" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeExpenseNet_019e69f8-3111-7506-8d0d-4cb926b6908c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestIncomeExpenseNet"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss_019e69f8-3111-7132-b49b-49c457b2ce57" xlink:to="loc_us-gaap_InterestIncomeExpenseNet_019e69f8-3111-7506-8d0d-4cb926b6908c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProvisionForLoanLossesExpensed_019e69f8-3111-7e9f-8504-a1245abd40c3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProvisionForLoanLossesExpensed"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss_019e69f8-3111-7132-b49b-49c457b2ce57" xlink:to="loc_us-gaap_ProvisionForLoanLossesExpensed_019e69f8-3111-7e9f-8504-a1245abd40c3" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossAttributableToParent_019e69f8-3111-7695-a60b-53c7e4b8bba8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossAttributableToParent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss_019e69f8-3111-785e-b327-9f352a686510" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossAttributableToParent_019e69f8-3111-7695-a60b-53c7e4b8bba8" xlink:to="loc_us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss_019e69f8-3111-785e-b327-9f352a686510" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestIncome_019e69f8-3111-7737-a787-bda6d417edbc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoninterestIncome"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossAttributableToParent_019e69f8-3111-7695-a60b-53c7e4b8bba8" xlink:to="loc_us-gaap_NoninterestIncome_019e69f8-3111-7737-a787-bda6d417edbc" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestExpense_019e69f8-3111-72d9-aecc-38a142d3cc72" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoninterestExpense"/>
    <link:calculationArc order="3" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossAttributableToParent_019e69f8-3111-7695-a60b-53c7e4b8bba8" xlink:to="loc_us-gaap_NoninterestExpense_019e69f8-3111-72d9-aecc-38a142d3cc72" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeExpenseNet_019e69f8-3111-79bb-8e69-419030282a8f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestIncomeExpenseNet"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestAndDividendIncomeOperating_019e69f8-3111-7d03-ad55-800bc1797023" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestAndDividendIncomeOperating"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_InterestIncomeExpenseNet_019e69f8-3111-79bb-8e69-419030282a8f" xlink:to="loc_us-gaap_InterestAndDividendIncomeOperating_019e69f8-3111-7d03-ad55-800bc1797023" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseOperating_019e69f8-3111-7eee-bcdc-17828c08533f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseOperating"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_InterestIncomeExpenseNet_019e69f8-3111-79bb-8e69-419030282a8f" xlink:to="loc_us-gaap_InterestExpenseOperating_019e69f8-3111-7eee-bcdc-17828c08533f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestAndDividendIncomeOperating_019e69f8-3111-7ec7-ac74-28e78eddbda5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestAndDividendIncomeOperating"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestAndFeeIncomeLoansAndLeases_019e69f8-3111-7c84-9b00-61a1cdce529f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestAndFeeIncomeLoansAndLeases"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_InterestAndDividendIncomeOperating_019e69f8-3111-7ec7-ac74-28e78eddbda5" xlink:to="loc_us-gaap_InterestAndFeeIncomeLoansAndLeases_019e69f8-3111-7c84-9b00-61a1cdce529f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeSecuritiesTaxable_019e69f8-3111-7719-bd84-21c364ac5f34" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestIncomeSecuritiesTaxable"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_InterestAndDividendIncomeOperating_019e69f8-3111-7ec7-ac74-28e78eddbda5" xlink:to="loc_us-gaap_InterestIncomeSecuritiesTaxable_019e69f8-3111-7719-bd84-21c364ac5f34" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeSecuritiesTaxExempt_019e69f8-3111-7777-9a84-9070f0d2e79a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestIncomeSecuritiesTaxExempt"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_InterestAndDividendIncomeOperating_019e69f8-3111-7ec7-ac74-28e78eddbda5" xlink:to="loc_us-gaap_InterestIncomeSecuritiesTaxExempt_019e69f8-3111-7777-9a84-9070f0d2e79a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendIncomeOperating_019e69f8-3111-7fe8-b48a-e085461840ad" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DividendIncomeOperating"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_InterestAndDividendIncomeOperating_019e69f8-3111-7ec7-ac74-28e78eddbda5" xlink:to="loc_us-gaap_DividendIncomeOperating_019e69f8-3111-7fe8-b48a-e085461840ad" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeFederalFundsSold_019e69f8-3111-7f7c-b5cf-e123d884188f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestIncomeFederalFundsSold"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_InterestAndDividendIncomeOperating_019e69f8-3111-7ec7-ac74-28e78eddbda5" xlink:to="loc_us-gaap_InterestIncomeFederalFundsSold_019e69f8-3111-7f7c-b5cf-e123d884188f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeDepositsWithFinancialInstitutions_019e69f8-3111-7239-ad1b-39369a290a5c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestIncomeDepositsWithFinancialInstitutions"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_InterestAndDividendIncomeOperating_019e69f8-3111-7ec7-ac74-28e78eddbda5" xlink:to="loc_us-gaap_InterestIncomeDepositsWithFinancialInstitutions_019e69f8-3111-7239-ad1b-39369a290a5c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestIncome_019e69f8-3111-7c02-93f7-4eb173ba3d9a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoninterestIncome"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss_019e69f8-3111-723f-b7f4-3067366aa054" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NoninterestIncome_019e69f8-3111-7c02-93f7-4eb173ba3d9a" xlink:to="loc_us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss_019e69f8-3111-723f-b7f4-3067366aa054" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSalesOfLoansNet_019e69f8-3111-74e8-9637-d376258952fd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnSalesOfLoansNet"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NoninterestIncome_019e69f8-3111-7c02-93f7-4eb173ba3d9a" xlink:to="loc_us-gaap_GainLossOnSalesOfLoansNet_019e69f8-3111-74e8-9637-d376258952fd" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_unb_WealthManagementIncome_019e69f8-3111-789a-92ea-63fcfe274bfd" xlink:href="unb-20260630.xsd#unb_WealthManagementIncome"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NoninterestIncome_019e69f8-3111-7c02-93f7-4eb173ba3d9a" xlink:to="loc_unb_WealthManagementIncome_019e69f8-3111-789a-92ea-63fcfe274bfd" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_unb_ServiceFees_019e69f8-3111-7096-8883-3c56fde2fbfc" xlink:href="unb-20260630.xsd#unb_ServiceFees"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NoninterestIncome_019e69f8-3111-7c02-93f7-4eb173ba3d9a" xlink:to="loc_unb_ServiceFees_019e69f8-3111-7096-8883-3c56fde2fbfc" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestIncomeOtherOperatingIncome_019e69f8-3111-7a85-9f7d-832371125df5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoninterestIncomeOtherOperatingIncome"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NoninterestIncome_019e69f8-3111-7c02-93f7-4eb173ba3d9a" xlink:to="loc_us-gaap_NoninterestIncomeOtherOperatingIncome_019e69f8-3111-7a85-9f7d-832371125df5" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestExpense_019e69f8-3111-7436-90ed-80efd0d3b1c6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoninterestExpense"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalariesWagesAndOfficersCompensation_019e69f8-31cd-7a0b-9def-163dc78becec" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SalariesWagesAndOfficersCompensation"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NoninterestExpense_019e69f8-3111-7436-90ed-80efd0d3b1c6" xlink:to="loc_us-gaap_SalariesWagesAndOfficersCompensation_019e69f8-31cd-7a0b-9def-163dc78becec" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherPostretirementBenefitExpense_019e69f8-31cd-7fd3-a0af-bb0b27f6ddf8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherPostretirementBenefitExpense"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NoninterestExpense_019e69f8-3111-7436-90ed-80efd0d3b1c6" xlink:to="loc_us-gaap_OtherPostretirementBenefitExpense_019e69f8-31cd-7fd3-a0af-bb0b27f6ddf8" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OccupancyNet_019e69f8-31cd-7559-aef6-b9cbac23f2e9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OccupancyNet"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NoninterestExpense_019e69f8-3111-7436-90ed-80efd0d3b1c6" xlink:to="loc_us-gaap_OccupancyNet_019e69f8-31cd-7559-aef6-b9cbac23f2e9" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquipmentExpense_019e69f8-31cd-76bf-8937-85e3ecb574ff" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquipmentExpense"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NoninterestExpense_019e69f8-3111-7436-90ed-80efd0d3b1c6" xlink:to="loc_us-gaap_EquipmentExpense_019e69f8-31cd-76bf-8937-85e3ecb574ff" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoninterestExpense_019e69f8-31cd-70cc-ae23-b0f2d3fc68eb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNoninterestExpense"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NoninterestExpense_019e69f8-3111-7436-90ed-80efd0d3b1c6" xlink:to="loc_us-gaap_OtherNoninterestExpense_019e69f8-31cd-70cc-ae23-b0f2d3fc68eb" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.unionbankvt.com/role/CONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOMEUnaudited" xlink:type="simple" xlink:href="unb-20260630.xsd#CONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOMEUnaudited"/>
  <link:calculationLink xlink:role="http://www.unionbankvt.com/role/CONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOMEUnaudited" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_019e69f8-31cd-728b-9b6a-0c9f0bdb8937" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ComprehensiveIncomeNetOfTax"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019e69f8-31cd-72e2-bc9d-b7a23f1fed03" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTax_019e69f8-31cd-728b-9b6a-0c9f0bdb8937" xlink:to="loc_us-gaap_NetIncomeLoss_019e69f8-31cd-72e2-bc9d-b7a23f1fed03" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019e69f8-31cd-708a-b83d-4ea08f97038d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTax_019e69f8-31cd-728b-9b6a-0c9f0bdb8937" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019e69f8-31cd-708a-b83d-4ea08f97038d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019e69f8-31cd-7937-ad9b-ce09ebd7d09b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_019e69f8-31cd-7946-be0e-20612299c749" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019e69f8-31cd-7937-ad9b-ce09ebd7d09b" xlink:to="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_019e69f8-31cd-7946-be0e-20612299c749" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.unionbankvt.com/role/CONSOLIDATEDSTATEMENTSOFCASHFLOWSUnaudited" xlink:type="simple" xlink:href="unb-20260630.xsd#CONSOLIDATEDSTATEMENTSOFCASHFLOWSUnaudited"/>
  <link:calculationLink xlink:role="http://www.unionbankvt.com/role/CONSOLIDATEDSTATEMENTSOFCASHFLOWSUnaudited" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_unb_PaymentsOfDividendsNetOfReinvestment_019e69f8-31cd-7ac2-81c8-e8399019a0f1" xlink:href="unb-20260630.xsd#unb_PaymentsOfDividendsNetOfReinvestment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfCommonStockDividendReinvestmentPlan_019e69f8-31cd-7398-a218-a97b99258f17" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIssuanceOfCommonStockDividendReinvestmentPlan"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_unb_PaymentsOfDividendsNetOfReinvestment_019e69f8-31cd-7ac2-81c8-e8399019a0f1" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfCommonStockDividendReinvestmentPlan_019e69f8-31cd-7398-a218-a97b99258f17" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfDividendsCommonStock_019e69f8-31cd-76f2-88d3-93a80ce5b910" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsOfDividendsCommonStock"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_unb_PaymentsOfDividendsNetOfReinvestment_019e69f8-31cd-7ac2-81c8-e8399019a0f1" xlink:to="loc_us-gaap_PaymentsOfDividendsCommonStock_019e69f8-31cd-76f2-88d3-93a80ce5b910" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_019e69f8-31cd-7f93-a800-66034b2f5e9b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e69f8-31cd-7ee2-8c1e-dbc0406240af" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_019e69f8-31cd-7f93-a800-66034b2f5e9b" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e69f8-31cd-7ee2-8c1e-dbc0406240af" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019e69f8-31cd-7f54-8e4d-d927dabd7497" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_019e69f8-31cd-7f93-a800-66034b2f5e9b" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019e69f8-31cd-7f54-8e4d-d927dabd7497" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019e69f8-31cd-73b4-b327-de39caf2c72d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_019e69f8-31cd-7f93-a800-66034b2f5e9b" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019e69f8-31cd-73b4-b327-de39caf2c72d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019e69f8-31cd-7614-9caf-f90c66b06539" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfLongTermDebt_019e69f8-31cd-73bf-a630-fa2c95b69953" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIssuanceOfLongTermDebt"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019e69f8-31cd-7614-9caf-f90c66b06539" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfLongTermDebt_019e69f8-31cd-73bf-a630-fa2c95b69953" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfLongTermDebt_019e69f8-31cd-778a-9cc5-a1232e9581f4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RepaymentsOfLongTermDebt"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019e69f8-31cd-7614-9caf-f90c66b06539" xlink:to="loc_us-gaap_RepaymentsOfLongTermDebt_019e69f8-31cd-778a-9cc5-a1232e9581f4" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromRepaymentsOfShortTermDebt_019e69f8-31cd-7e1b-9d01-1f20299f9d44" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromRepaymentsOfShortTermDebt"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019e69f8-31cd-7614-9caf-f90c66b06539" xlink:to="loc_us-gaap_ProceedsFromRepaymentsOfShortTermDebt_019e69f8-31cd-7e1b-9d01-1f20299f9d44" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_unb_NetIncreaseDecreaseInNoninterestBearingDeposits_019e69f8-31cd-7015-8806-94c4034121e0" xlink:href="unb-20260630.xsd#unb_NetIncreaseDecreaseInNoninterestBearingDeposits"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019e69f8-31cd-7614-9caf-f90c66b06539" xlink:to="loc_unb_NetIncreaseDecreaseInNoninterestBearingDeposits_019e69f8-31cd-7015-8806-94c4034121e0" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_unb_NetChangeInterestBearingNonTimeDeposits_019e69f8-31cd-7604-aefb-f5f3da41cc57" xlink:href="unb-20260630.xsd#unb_NetChangeInterestBearingNonTimeDeposits"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019e69f8-31cd-7614-9caf-f90c66b06539" xlink:to="loc_unb_NetChangeInterestBearingNonTimeDeposits_019e69f8-31cd-7604-aefb-f5f3da41cc57" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInTimeDeposits_019e69f8-31cd-7696-b19b-25abbe588c3b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInTimeDeposits"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019e69f8-31cd-7614-9caf-f90c66b06539" xlink:to="loc_us-gaap_IncreaseDecreaseInTimeDeposits_019e69f8-31cd-7696-b19b-25abbe588c3b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_unb_PaymentsOfDividendsNetOfReinvestment_019e69f8-31cd-7983-bec3-8ad672acb846" xlink:href="unb-20260630.xsd#unb_PaymentsOfDividendsNetOfReinvestment"/>
    <link:calculationArc order="7" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019e69f8-31cd-7614-9caf-f90c66b06539" xlink:to="loc_unb_PaymentsOfDividendsNetOfReinvestment_019e69f8-31cd-7983-bec3-8ad672acb846" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_019f69ed-dfa2-745c-8e7a-d23d39a21771" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock"/>
    <link:calculationArc order="8" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019e69f8-31cd-7614-9caf-f90c66b06539" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_019f69ed-dfa2-745c-8e7a-d23d39a21771" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019e69f8-31cd-7808-afe8-8fa1d9c8934f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <link:loc xlink:type="locator" xlink:label="loc_unb_ProceedsFromInterestBearingDepositsInBanks_019e69f8-31cd-7c8c-9bb3-9c1074b4eb82" xlink:href="unb-20260630.xsd#unb_ProceedsFromInterestBearingDepositsInBanks"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019e69f8-31cd-7808-afe8-8fa1d9c8934f" xlink:to="loc_unb_ProceedsFromInterestBearingDepositsInBanks_019e69f8-31cd-7c8c-9bb3-9c1074b4eb82" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_unb_PaymentsForInterestBearingDepositsInBanks_019e69f8-31cd-76d8-a633-dcdd68952bf0" xlink:href="unb-20260630.xsd#unb_PaymentsForInterestBearingDepositsInBanks"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019e69f8-31cd-7808-afe8-8fa1d9c8934f" xlink:to="loc_unb_PaymentsForInterestBearingDepositsInBanks_019e69f8-31cd-76d8-a633-dcdd68952bf0" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_019e69f8-31cd-7eab-b398-2b97dabd9e79" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019e69f8-31cd-7808-afe8-8fa1d9c8934f" xlink:to="loc_us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_019e69f8-31cd-7eab-b398-2b97dabd9e79" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_unb_PaymentsForProceedsFromOtherInvestments_019e69f8-31cd-70bb-acaa-0374e6ff4ebd" xlink:href="unb-20260630.xsd#unb_PaymentsForProceedsFromOtherInvestments"/>
    <link:calculationArc order="4" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019e69f8-31cd-7808-afe8-8fa1d9c8934f" xlink:to="loc_unb_PaymentsForProceedsFromOtherInvestments_019e69f8-31cd-70bb-acaa-0374e6ff4ebd" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForProceedsFromFederalHomeLoanBankStock_019e69f8-31cd-72f1-9616-c20554db7550" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsForProceedsFromFederalHomeLoanBankStock"/>
    <link:calculationArc order="5" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019e69f8-31cd-7808-afe8-8fa1d9c8934f" xlink:to="loc_us-gaap_PaymentsForProceedsFromFederalHomeLoanBankStock_019e69f8-31cd-72f1-9616-c20554db7550" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForProceedsFromOtherLoansAndLeases_019e69f8-31cd-7e88-baba-135cd565ca91" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsForProceedsFromOtherLoansAndLeases"/>
    <link:calculationArc order="6" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019e69f8-31cd-7808-afe8-8fa1d9c8934f" xlink:to="loc_us-gaap_PaymentsForProceedsFromOtherLoansAndLeases_019e69f8-31cd-7e88-baba-135cd565ca91" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromRecoveriesOfLoanPreviouslyChargedOff_019e69f8-31cd-76b4-b07d-d060810f1bac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromRecoveriesOfLoanPreviouslyChargedOff"/>
    <link:calculationArc order="7" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019e69f8-31cd-7808-afe8-8fa1d9c8934f" xlink:to="loc_us-gaap_ProceedsFromRecoveriesOfLoanPreviouslyChargedOff_019e69f8-31cd-76b4-b07d-d060810f1bac" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_019e69f8-31cd-79bb-8bb8-5fe4dd04e21b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment"/>
    <link:calculationArc order="8" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019e69f8-31cd-7808-afe8-8fa1d9c8934f" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_019e69f8-31cd-79bb-8bb8-5fe4dd04e21b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireLimitedPartnershipInterests_019e69f8-31cd-7d04-acc1-c783256d6a26" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToAcquireLimitedPartnershipInterests"/>
    <link:calculationArc order="9" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019e69f8-31cd-7808-afe8-8fa1d9c8934f" xlink:to="loc_us-gaap_PaymentsToAcquireLimitedPartnershipInterests_019e69f8-31cd-7d04-acc1-c783256d6a26" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_019f8a8f-831e-7004-89a4-5f3869f1606f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment"/>
    <link:calculationArc order="10" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019e69f8-31cd-7808-afe8-8fa1d9c8934f" xlink:to="loc_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_019f8a8f-831e-7004-89a4-5f3869f1606f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e69f8-31cd-7a98-8305-1f0a377df136" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019e69f8-31cd-736b-94d6-7810bddfbda3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e69f8-31cd-7a98-8305-1f0a377df136" xlink:to="loc_us-gaap_NetIncomeLoss_019e69f8-31cd-736b-94d6-7810bddfbda3" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationAmortizationAndAccretionNet_019e69f8-31cd-7732-8665-1c789e9ca07a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DepreciationAmortizationAndAccretionNet"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e69f8-31cd-7a98-8305-1f0a377df136" xlink:to="loc_us-gaap_DepreciationAmortizationAndAccretionNet_019e69f8-31cd-7732-8665-1c789e9ca07a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProvisionForLoanLeaseAndOtherLosses_019e69f8-31cd-7a76-b98c-078ba2b078e3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProvisionForLoanLeaseAndOtherLosses"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e69f8-31cd-7a98-8305-1f0a377df136" xlink:to="loc_us-gaap_ProvisionForLoanLeaseAndOtherLosses_019e69f8-31cd-7a76-b98c-078ba2b078e3" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxExpenseBenefit_019e69f8-31cd-7b1f-9fa5-840dd15d268b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredIncomeTaxExpenseBenefit"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e69f8-31cd-7a98-8305-1f0a377df136" xlink:to="loc_us-gaap_DeferredIncomeTaxExpenseBenefit_019e69f8-31cd-7b1f-9fa5-840dd15d268b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments_019e69f8-31cd-7d19-8cbb-060adc904d96" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments"/>
    <link:calculationArc order="5" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e69f8-31cd-7a98-8305-1f0a377df136" xlink:to="loc_us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments_019e69f8-31cd-7d19-8cbb-060adc904d96" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization_019e69f8-31cd-75cd-8073-43732c521197" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e69f8-31cd-7a98-8305-1f0a377df136" xlink:to="loc_us-gaap_AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization_019e69f8-31cd-75cd-8073-43732c521197" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensation_019e69f8-31cd-727b-b52d-f7e58591e714" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensation"/>
    <link:calculationArc order="7" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e69f8-31cd-7a98-8305-1f0a377df136" xlink:to="loc_us-gaap_ShareBasedCompensation_019e69f8-31cd-727b-b52d-f7e58591e714" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInLoansDeferredIncome_019e69f8-31cd-7d31-a1fd-d8969f0b6af2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInLoansDeferredIncome"/>
    <link:calculationArc order="8" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e69f8-31cd-7a98-8305-1f0a377df136" xlink:to="loc_us-gaap_IncreaseDecreaseInLoansDeferredIncome_019e69f8-31cd-7d31-a1fd-d8969f0b6af2" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleOfLoansHeldForSale_019e69f8-31cd-7b68-a16c-46d7bb229164" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromSaleOfLoansHeldForSale"/>
    <link:calculationArc order="9" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e69f8-31cd-7a98-8305-1f0a377df136" xlink:to="loc_us-gaap_ProceedsFromSaleOfLoansHeldForSale_019e69f8-31cd-7b68-a16c-46d7bb229164" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForOriginationAndPurchasesOfLoansHeldForSale_019e69f8-31cd-7dba-bad8-199124f29127" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsForOriginationAndPurchasesOfLoansHeldForSale"/>
    <link:calculationArc order="10" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e69f8-31cd-7a98-8305-1f0a377df136" xlink:to="loc_us-gaap_PaymentsForOriginationAndPurchasesOfLoansHeldForSale_019e69f8-31cd-7dba-bad8-199124f29127" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSalesOfLoansNet_019e69f8-31cd-7ef5-869d-03ea8398e904" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnSalesOfLoansNet"/>
    <link:calculationArc order="11" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e69f8-31cd-7a98-8305-1f0a377df136" xlink:to="loc_us-gaap_GainLossOnSalesOfLoansNet_019e69f8-31cd-7ef5-869d-03ea8398e904" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInEquitySecuritiesFvNi_019e69f8-31cd-7e73-ab6c-5de933783446" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInEquitySecuritiesFvNi"/>
    <link:calculationArc order="12" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e69f8-31cd-7a98-8305-1f0a377df136" xlink:to="loc_us-gaap_IncreaseDecreaseInEquitySecuritiesFvNi_019e69f8-31cd-7e73-ab6c-5de933783446" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccruedInterestReceivableNet_019e69f8-31cd-767f-8cf1-c240de78dd96" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInAccruedInterestReceivableNet"/>
    <link:calculationArc order="13" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e69f8-31cd-7a98-8305-1f0a377df136" xlink:to="loc_us-gaap_IncreaseDecreaseInAccruedInterestReceivableNet_019e69f8-31cd-767f-8cf1-c240de78dd96" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfFinancingCosts_019e69f8-31cd-7e86-93f7-b29a185ba91a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AmortizationOfFinancingCosts"/>
    <link:calculationArc order="14" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e69f8-31cd-7a98-8305-1f0a377df136" xlink:to="loc_us-gaap_AmortizationOfFinancingCosts_019e69f8-31cd-7e86-93f7-b29a185ba91a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssets_019e69f8-31cd-77bf-b5b8-dd50304bb2f7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInOtherOperatingAssets"/>
    <link:calculationArc order="15" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e69f8-31cd-7a98-8305-1f0a377df136" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssets_019e69f8-31cd-77bf-b5b8-dd50304bb2f7" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_019e69f8-31cd-7622-9bd7-3b70dcd433e1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInOtherOperatingLiabilities"/>
    <link:calculationArc order="16" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e69f8-31cd-7a98-8305-1f0a377df136" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_019e69f8-31cd-7622-9bd7-3b70dcd433e1" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfPropertyPlantEquipment_019f8a8f-4a87-7fb1-a958-dbb292f889d4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnSaleOfPropertyPlantEquipment"/>
    <link:calculationArc order="17" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e69f8-31cd-7a98-8305-1f0a377df136" xlink:to="loc_us-gaap_GainLossOnSaleOfPropertyPlantEquipment_019f8a8f-4a87-7fb1-a958-dbb292f889d4" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.unionbankvt.com/role/PerShareInformationScheduleofEarningsPerShareBasicandDilutedDetails" xlink:type="simple" xlink:href="unb-20260630.xsd#PerShareInformationScheduleofEarningsPerShareBasicandDilutedDetails"/>
  <link:calculationLink xlink:role="http://www.unionbankvt.com/role/PerShareInformationScheduleofEarningsPerShareBasicandDilutedDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019e69f8-31cd-7c9f-bd2b-9d6d4a68b46c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment_019e69f8-31cd-7295-a57e-b9fb33c0e717" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019e69f8-31cd-7c9f-bd2b-9d6d4a68b46c" xlink:to="loc_us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment_019e69f8-31cd-7295-a57e-b9fb33c0e717" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019e69f8-31cd-792b-a56a-e692b330b059" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019e69f8-31cd-7c9f-bd2b-9d6d4a68b46c" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019e69f8-31cd-792b-a56a-e692b330b059" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.unionbankvt.com/role/InvestmentSecuritiesScheduleofDebtSecuritiesAvailableforsaleDetails" xlink:type="simple" xlink:href="unb-20260630.xsd#InvestmentSecuritiesScheduleofDebtSecuritiesAvailableforsaleDetails"/>
  <link:calculationLink xlink:role="http://www.unionbankvt.com/role/InvestmentSecuritiesScheduleofDebtSecuritiesAvailableforsaleDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e69f8-31cd-7879-9031-e181327da1b7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_019e69f8-31cd-7fb7-9589-a928f2b1917c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e69f8-31cd-7879-9031-e181327da1b7" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_019e69f8-31cd-7fb7-9589-a928f2b1917c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_019e69f8-31cd-79e3-a308-a01862c2444e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e69f8-31cd-7879-9031-e181327da1b7" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_019e69f8-31cd-79e3-a308-a01862c2444e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_019e69f8-31cd-7f9d-9302-0459c276ce64" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e69f8-31cd-7879-9031-e181327da1b7" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_019e69f8-31cd-7f9d-9302-0459c276ce64" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.unionbankvt.com/role/InvestmentSecuritiesScheduleofInvestmentsClassifiedbyContractualMaturityDateDetails" xlink:type="simple" xlink:href="unb-20260630.xsd#InvestmentSecuritiesScheduleofInvestmentsClassifiedbyContractualMaturityDateDetails"/>
  <link:calculationLink xlink:role="http://www.unionbankvt.com/role/InvestmentSecuritiesScheduleofInvestmentsClassifiedbyContractualMaturityDateDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_019e69f8-31cd-7ddd-9607-965fa2cd2e8b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate_019e69f8-31cd-7b6a-86a6-e5ce5564bdbe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_019e69f8-31cd-7ddd-9607-965fa2cd2e8b" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate_019e69f8-31cd-7b6a-86a6-e5ce5564bdbe" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue_019e69f8-31cd-75b1-9e41-7591ead9e7e4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_019e69f8-31cd-7ddd-9607-965fa2cd2e8b" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue_019e69f8-31cd-75b1-9e41-7591ead9e7e4" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis_019e69f8-31cd-7b65-b084-416b4157cf9a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis_019e69f8-31cd-7e18-8052-279815b529b7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis_019e69f8-31cd-7b65-b084-416b4157cf9a" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis_019e69f8-31cd-7e18-8052-279815b529b7" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis_019e69f8-31cd-7c08-901b-19008cdcb9a2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis_019e69f8-31cd-7b65-b084-416b4157cf9a" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis_019e69f8-31cd-7c08-901b-19008cdcb9a2" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis_019e69f8-31cd-7709-a8ec-64341a4743ba" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis_019e69f8-31cd-7b65-b084-416b4157cf9a" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis_019e69f8-31cd-7709-a8ec-64341a4743ba" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis_019e69f8-31cd-78e6-8893-b2520de3f508" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis_019e69f8-31cd-7b65-b084-416b4157cf9a" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis_019e69f8-31cd-78e6-8893-b2520de3f508" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate_019e69f8-31cd-7629-ac54-7f7b2396c94d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue_019e69f8-31cd-79c9-ad48-9162971e2036" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate_019e69f8-31cd-7629-ac54-7f7b2396c94d" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue_019e69f8-31cd-79c9-ad48-9162971e2036" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue_019e69f8-31cd-74b7-8091-792856380b70" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate_019e69f8-31cd-7629-ac54-7f7b2396c94d" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue_019e69f8-31cd-74b7-8091-792856380b70" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue_019e69f8-31cd-744a-aac3-36be5cf78d6b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate_019e69f8-31cd-7629-ac54-7f7b2396c94d" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue_019e69f8-31cd-744a-aac3-36be5cf78d6b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue_019e69f8-31cd-7122-9ffa-a94da01950ad" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate_019e69f8-31cd-7629-ac54-7f7b2396c94d" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue_019e69f8-31cd-7122-9ffa-a94da01950ad" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss_019e69f8-31cd-7f7c-812b-02b2f997d772" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost_019e69f8-31cd-7611-ab9a-00cb3fbb365d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss_019e69f8-31cd-7f7c-812b-02b2f997d772" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost_019e69f8-31cd-7611-ab9a-00cb3fbb365d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis_019e69f8-31cd-78bb-ab9d-2ca22f22650a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss_019e69f8-31cd-7f7c-812b-02b2f997d772" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis_019e69f8-31cd-78bb-ab9d-2ca22f22650a" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.unionbankvt.com/role/InvestmentSecuritiesScheduleofUnrealizedLossonInvestmentsDetails" xlink:type="simple" xlink:href="unb-20260630.xsd#InvestmentSecuritiesScheduleofUnrealizedLossonInvestmentsDetails"/>
  <link:calculationLink xlink:role="http://www.unionbankvt.com/role/InvestmentSecuritiesScheduleofUnrealizedLossonInvestmentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions_019e69f8-31cd-7964-8bad-d40142c6ed7c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositions_019e69f8-31cd-7ef6-b96b-172ee4d1a350" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositions"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions_019e69f8-31cd-7964-8bad-d40142c6ed7c" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositions_019e69f8-31cd-7ef6-b96b-172ee4d1a350" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions_019e69f8-31cd-73a0-95e9-a0093204c75e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions_019e69f8-31cd-7964-8bad-d40142c6ed7c" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions_019e69f8-31cd-73a0-95e9-a0093204c75e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss_019e69f8-31cd-7322-8b2d-a61b720219ed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_019e69f8-31cd-79e7-9ded-ba81907e6cb7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss_019e69f8-31cd-7322-8b2d-a61b720219ed" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_019e69f8-31cd-79e7-9ded-ba81907e6cb7" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_019e69f8-31cd-7f95-ad88-429b1cc18457" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss_019e69f8-31cd-7322-8b2d-a61b720219ed" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_019e69f8-31cd-7f95-ad88-429b1cc18457" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_019e69f8-31cd-7ff0-8aeb-633c5714e1eb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_019e69f8-31cd-719f-a240-fc6ca9ef4819" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_019e69f8-31cd-7ff0-8aeb-633c5714e1eb" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_019e69f8-31cd-719f-a240-fc6ca9ef4819" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_019e69f8-31cd-78e0-8996-2b33e0a5ce97" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_019e69f8-31cd-7ff0-8aeb-633c5714e1eb" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_019e69f8-31cd-78e0-8996-2b33e0a5ce97" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.unionbankvt.com/role/LoansScheduleofCompositionofNetLoansDetails" xlink:type="simple" xlink:href="unb-20260630.xsd#LoansScheduleofCompositionofNetLoansDetails"/>
  <link:calculationLink xlink:role="http://www.unionbankvt.com/role/LoansScheduleofCompositionofNetLoansDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss_019e69f8-31cd-7e0e-af8b-8be9e43a2dfc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e69f8-31cd-7a2f-b3bf-84a45d393cce" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss_019e69f8-31cd-7e0e-af8b-8be9e43a2dfc" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e69f8-31cd-7a2f-b3bf-84a45d393cce" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_019e69f8-31cd-7e57-a97a-e05f1c40af39" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss_019e69f8-31cd-7e0e-af8b-8be9e43a2dfc" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_019e69f8-31cd-7e57-a97a-e05f1c40af39" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableUnamortizedLoanFeeCost_019e69f8-31cd-70ae-ba8c-167966327953" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableUnamortizedLoanFeeCost"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss_019e69f8-31cd-7e0e-af8b-8be9e43a2dfc" xlink:to="loc_us-gaap_FinancingReceivableUnamortizedLoanFeeCost_019e69f8-31cd-70ae-ba8c-167966327953" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.unionbankvt.com/role/AllowanceforCreditLossesonLoansandOffBalanceSheetCreditExposuresScheduleofFinancingReceivableCreditQualityIndicatorsDetails" xlink:type="simple" xlink:href="unb-20260630.xsd#AllowanceforCreditLossesonLoansandOffBalanceSheetCreditExposuresScheduleofFinancingReceivableCreditQualityIndicatorsDetails"/>
  <link:calculationLink xlink:role="http://www.unionbankvt.com/role/AllowanceforCreditLossesonLoansandOffBalanceSheetCreditExposuresScheduleofFinancingReceivableCreditQualityIndicatorsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff_019e69f8-31ce-7a52-938c-ddbf70ab0bf3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearWriteoff_019e69f8-31ce-73ba-bd25-e188fa86a676" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearWriteoff"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff_019e69f8-31ce-7a52-938c-ddbf70ab0bf3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearWriteoff_019e69f8-31ce-73ba-bd25-e188fa86a676" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff_019e69f8-31ce-7240-b6a8-7e205f9e305d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff_019e69f8-31ce-7a52-938c-ddbf70ab0bf3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff_019e69f8-31ce-7240-b6a8-7e205f9e305d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff_019e69f8-31ce-7a80-be1c-a446f851329e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff_019e69f8-31ce-7a52-938c-ddbf70ab0bf3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff_019e69f8-31ce-7a80-be1c-a446f851329e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff_019e69f8-31ce-776c-9e43-4c3269c373d4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff_019e69f8-31ce-7a52-938c-ddbf70ab0bf3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff_019e69f8-31ce-776c-9e43-4c3269c373d4" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff_019e69f8-31ce-755a-85e6-204f806adf11" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff_019e69f8-31ce-7a52-938c-ddbf70ab0bf3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff_019e69f8-31ce-755a-85e6-204f806adf11" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearWriteoff_019e69f8-31ce-7245-a0fb-dad2fd490f91" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearWriteoff"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff_019e69f8-31ce-7a52-938c-ddbf70ab0bf3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearWriteoff_019e69f8-31ce-7245-a0fb-dad2fd490f91" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingWriteoff_019e69f8-31ce-7af2-a091-3200ef7c0af4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingWriteoff"/>
    <link:calculationArc order="7" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff_019e69f8-31ce-7a52-938c-ddbf70ab0bf3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingWriteoff_019e69f8-31ce-7af2-a091-3200ef7c0af4" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e69f8-31ce-7d84-b534-6455be11b8ac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear_019e69f8-31ce-7982-9464-d59c6ad24f39" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e69f8-31ce-7d84-b534-6455be11b8ac" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear_019e69f8-31ce-7982-9464-d59c6ad24f39" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear_019e69f8-31ce-779f-9714-8f349cb37187" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e69f8-31ce-7d84-b534-6455be11b8ac" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear_019e69f8-31ce-779f-9714-8f349cb37187" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear_019e69f8-31ce-7b3b-b718-52204e78df6f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e69f8-31ce-7d84-b534-6455be11b8ac" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear_019e69f8-31ce-7b3b-b718-52204e78df6f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear_019e69f8-31ce-7214-957a-7e3c20cd721d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e69f8-31ce-7d84-b534-6455be11b8ac" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear_019e69f8-31ce-7214-957a-7e3c20cd721d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear_019e69f8-31ce-712f-a3fe-1f6e70722e89" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e69f8-31ce-7d84-b534-6455be11b8ac" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear_019e69f8-31ce-712f-a3fe-1f6e70722e89" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear_019e69f8-31ce-7aec-9e5a-4c5eb5bfb83b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e69f8-31ce-7d84-b534-6455be11b8ac" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear_019e69f8-31ce-7aec-9e5a-4c5eb5bfb83b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestRevolving_019e69f8-31ce-7d95-a9ea-f98f820a7f3f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestRevolving"/>
    <link:calculationArc order="7" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e69f8-31ce-7d84-b534-6455be11b8ac" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestRevolving_019e69f8-31ce-7d95-a9ea-f98f820a7f3f" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.unionbankvt.com/role/OtherComprehensiveIncomeScheduleofTaxEffectsAllocatedtoEachComponentofOCIDetails" xlink:type="simple" xlink:href="unb-20260630.xsd#OtherComprehensiveIncomeScheduleofTaxEffectsAllocatedtoEachComponentofOCIDetails"/>
  <link:calculationLink xlink:role="http://www.unionbankvt.com/role/OtherComprehensiveIncomeScheduleofTaxEffectsAllocatedtoEachComponentofOCIDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent_019e69f8-31ce-779c-b791-7a9773dd3a1f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax_019e69f8-31ce-7e1a-8ce4-1a3fc60ebe82" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent_019e69f8-31ce-779c-b791-7a9773dd3a1f" xlink:to="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax_019e69f8-31ce-7e1a-8ce4-1a3fc60ebe82" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019e69f8-31ce-7f21-803d-ff6b12a8229e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_019e69f8-31ce-732f-9cf5-f0337562f8f2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019e69f8-31ce-7f21-803d-ff6b12a8229e" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_019e69f8-31ce-732f-9cf5-f0337562f8f2" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent_019e69f8-31ce-75d2-9296-af09933db1d3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019e69f8-31ce-7f21-803d-ff6b12a8229e" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent_019e69f8-31ce-75d2-9296-af09933db1d3" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_019e69f8-31ce-7dbb-a7f1-fa4d075f98a0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax_019e69f8-31ce-7034-9c8c-23fed9d40d06" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_019e69f8-31ce-7dbb-a7f1-fa4d075f98a0" xlink:to="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax_019e69f8-31ce-7034-9c8c-23fed9d40d06" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax_019e69f8-31ce-79f2-a3e3-a9de1f0d0083" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_019e69f8-31ce-7dbb-a7f1-fa4d075f98a0" xlink:to="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax_019e69f8-31ce-79f2-a3e3-a9de1f0d0083" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_019e69f8-31ce-7581-99f6-233f9fe5d1f7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax_019e69f8-31ce-7b05-b2af-cc9b22c26481" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_019e69f8-31ce-7581-99f6-233f9fe5d1f7" xlink:to="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax_019e69f8-31ce-7b05-b2af-cc9b22c26481" xlink:type="arc"/>
  </link:calculationLink>
</link:linkbase>
