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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019e22aa-3c28-7464-acd5-fe9d15ba6050,g:b7191df2-6599-4b09-8737-ddd6c410b821-->
<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.kbr.com/role/CondensedConsolidatedStatementsofOperations" xlink:type="simple" xlink:href="kbr-20260703.xsd#CondensedConsolidatedStatementsofOperations"/>
  <link:calculationLink xlink:role="http://www.kbr.com/role/CondensedConsolidatedStatementsofOperations" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_019e22aa-3ed8-75bf-8598-110addcb9396" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GrossProfit_019e22aa-3ed8-786f-b1a1-3e4337554571" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GrossProfit"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss_019e22aa-3ed8-75bf-8598-110addcb9396" xlink:to="loc_us-gaap_GrossProfit_019e22aa-3ed8-786f-b1a1-3e4337554571" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_019e22aa-3ed8-793f-a74d-6e3617064e41" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss_019e22aa-3ed8-75bf-8598-110addcb9396" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_019e22aa-3ed8-793f-a74d-6e3617064e41" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_019e22aa-3ed8-78cf-a735-1f3e11cb4478" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SellingGeneralAndAdministrativeExpense"/>
    <link:calculationArc order="3" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss_019e22aa-3ed8-75bf-8598-110addcb9396" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_019e22aa-3ed8-78cf-a735-1f3e11cb4478" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostsAndAssetImpairmentCharges_019e22aa-3ed8-7392-ac46-d1e41befc49a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestructuringCostsAndAssetImpairmentCharges"/>
    <link:calculationArc order="4" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss_019e22aa-3ed8-75bf-8598-110addcb9396" xlink:to="loc_us-gaap_RestructuringCostsAndAssetImpairmentCharges_019e22aa-3ed8-7392-ac46-d1e41befc49a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherOperatingIncomeExpenseNet_019f41f6-e8e1-723b-9a6a-ab01a1bcc656" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherOperatingIncomeExpenseNet"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss_019e22aa-3ed8-75bf-8598-110addcb9396" xlink:to="loc_us-gaap_OtherOperatingIncomeExpenseNet_019f41f6-e8e1-723b-9a6a-ab01a1bcc656" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest_019e22aa-3ed8-7b97-b7bf-0e354200ab52" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_019e22aa-3ed8-7874-a33a-42c5a250db08" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest_019e22aa-3ed8-7b97-b7bf-0e354200ab52" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_019e22aa-3ed8-7874-a33a-42c5a250db08" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e22aa-3ed8-781e-94f1-31fdbf66f944" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest_019e22aa-3ed8-7b97-b7bf-0e354200ab52" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e22aa-3ed8-781e-94f1-31fdbf66f944" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e22aa-3ed8-7f98-9ec1-ab95e729a7ea" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseNonoperating_019e22aa-3ed8-79c9-9ada-064ee474d650" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseNonoperating"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e22aa-3ed8-7f98-9ec1-ab95e729a7ea" xlink:to="loc_us-gaap_InterestExpenseNonoperating_019e22aa-3ed8-79c9-9ada-064ee474d650" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_019e22aa-3ed8-7164-9b17-5e5f91b60d8f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e22aa-3ed8-7f98-9ec1-ab95e729a7ea" xlink:to="loc_us-gaap_OperatingIncomeLoss_019e22aa-3ed8-7164-9b17-5e5f91b60d8f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_019e22aa-3ed8-7325-933c-7c318e003aad" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e22aa-3ed8-7f98-9ec1-ab95e729a7ea" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_019e22aa-3ed8-7325-933c-7c318e003aad" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_019e22aa-3ed8-70a3-be07-5aadf676088e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProfitLoss"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest_019e22aa-3ed8-712b-a88e-86836bd54af2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_ProfitLoss_019e22aa-3ed8-70a3-be07-5aadf676088e" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest_019e22aa-3ed8-712b-a88e-86836bd54af2" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodNetOfTax_019e22aa-3ed8-7331-a467-94683699a963" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodNetOfTax"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_ProfitLoss_019e22aa-3ed8-70a3-be07-5aadf676088e" xlink:to="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodNetOfTax_019e22aa-3ed8-7331-a467-94683699a963" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_019e22aa-3ed8-756c-a777-abb5a0bd48ef" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare_019e22aa-3ed8-7a96-9a9c-b308afe1ba00" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_EarningsPerShareDiluted_019e22aa-3ed8-756c-a777-abb5a0bd48ef" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare_019e22aa-3ed8-7a96-9a9c-b308afe1ba00" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerDilutedShare_019e22aa-3ed8-7d4b-83aa-a9b1a3bdda0c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerDilutedShare"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_EarningsPerShareDiluted_019e22aa-3ed8-756c-a777-abb5a0bd48ef" xlink:to="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerDilutedShare_019e22aa-3ed8-7d4b-83aa-a9b1a3bdda0c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_019e22aa-3ed8-728c-a217-c38d54d7d0b5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare_019e22aa-3ed8-7f89-9a16-93dce870eb47" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsPerBasicShare"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_EarningsPerShareBasic_019e22aa-3ed8-728c-a217-c38d54d7d0b5" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare_019e22aa-3ed8-7f89-9a16-93dce870eb47" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare_019e22aa-3ed8-76e2-847a-7e87fe71430a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_EarningsPerShareBasic_019e22aa-3ed8-728c-a217-c38d54d7d0b5" xlink:to="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare_019e22aa-3ed8-76e2-847a-7e87fe71430a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GrossProfit_019e22aa-3ed8-71f7-8fe1-120a7ac3f9ac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GrossProfit"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_019e22aa-3ed8-779d-a467-720ed5c9bd71" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_GrossProfit_019e22aa-3ed8-71f7-8fe1-120a7ac3f9ac" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_019e22aa-3ed8-779d-a467-720ed5c9bd71" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e22aa-3ed8-7e1d-8c1c-e5aa2ae406f4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_GrossProfit_019e22aa-3ed8-71f7-8fe1-120a7ac3f9ac" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e22aa-3ed8-7e1d-8c1c-e5aa2ae406f4" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019e22aa-3ed8-7846-9b2d-05c05609d0b0" 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_ProfitLoss_019e22aa-3ed8-7a68-9afe-950ee2c4d41f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProfitLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss_019e22aa-3ed8-7846-9b2d-05c05609d0b0" xlink:to="loc_us-gaap_ProfitLoss_019e22aa-3ed8-7a68-9afe-950ee2c4d41f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsAttributableToNoncontrollingEntity_019e22aa-3ed8-751e-8757-3e2e6b7ff473" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsAttributableToNoncontrollingEntity"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss_019e22aa-3ed8-7846-9b2d-05c05609d0b0" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsAttributableToNoncontrollingEntity_019e22aa-3ed8-751e-8757-3e2e6b7ff473" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest_019e22aa-3ed8-7ed0-bfa6-734b04e8fce1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest"/>
    <link:calculationArc order="3" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss_019e22aa-3ed8-7846-9b2d-05c05609d0b0" xlink:to="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest_019e22aa-3ed8-7ed0-bfa6-734b04e8fce1" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.kbr.com/role/CondensedConsolidatedStatementsofComprehensiveIncome" xlink:type="simple" xlink:href="kbr-20260703.xsd#CondensedConsolidatedStatementsofComprehensiveIncome"/>
  <link:calculationLink xlink:role="http://www.kbr.com/role/CondensedConsolidatedStatementsofComprehensiveIncome" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_019e22aa-3ed8-7d2c-a88d-d0522597e7e6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_019e22aa-3ed8-73bd-811c-1cf3d0a04c9d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProfitLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_019e22aa-3ed8-7d2c-a88d-d0522597e7e6" xlink:to="loc_us-gaap_ProfitLoss_019e22aa-3ed8-73bd-811c-1cf3d0a04c9d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_019e22aa-3ed8-78c1-9360-9ba7d1027a4b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_019e22aa-3ed8-7d2c-a88d-d0522597e7e6" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_019e22aa-3ed8-78c1-9360-9ba7d1027a4b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_019e22aa-3ed8-704d-99cc-b4cd68201548" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTax_019e22aa-3ed8-7c34-ad11-9888cdb5082c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeTax"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_019e22aa-3ed8-704d-99cc-b4cd68201548" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTax_019e22aa-3ed8-7c34-ad11-9888cdb5082c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossTax_019e22aa-3ed8-7325-9165-1279f204143e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossTax"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_019e22aa-3ed8-704d-99cc-b4cd68201548" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossTax_019e22aa-3ed8-7325-9165-1279f204143e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossTax_019e22aa-3ed8-78f0-aa65-af7d87cec2b0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossTax"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax_019e22aa-3ed8-708c-a4d5-48faf0f8bec4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossTax_019e22aa-3ed8-78f0-aa65-af7d87cec2b0" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax_019e22aa-3ed8-708c-a4d5-48faf0f8bec4" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax_019e22aa-3ed8-7a83-94e5-9cf8d14a7fd8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossTax_019e22aa-3ed8-78f0-aa65-af7d87cec2b0" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax_019e22aa-3ed8-7a83-94e5-9cf8d14a7fd8" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_019e22aa-3ed8-7a62-9254-6ef183663499" 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_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_019e22aa-3ed8-7c17-b0ae-1186b7ef1078" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTax_019e22aa-3ed8-7a62-9254-6ef183663499" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_019e22aa-3ed8-7c17-b0ae-1186b7ef1078" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_kbr_ComprehensiveIncomeLossNetOfTaxAttributableToNoncontrollingInterestContinuingOperations_019e22aa-3ed8-70ae-aad0-92c2a4013f18" xlink:href="kbr-20260703.xsd#kbr_ComprehensiveIncomeLossNetOfTaxAttributableToNoncontrollingInterestContinuingOperations"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTax_019e22aa-3ed8-7a62-9254-6ef183663499" xlink:to="loc_kbr_ComprehensiveIncomeLossNetOfTaxAttributableToNoncontrollingInterestContinuingOperations_019e22aa-3ed8-70ae-aad0-92c2a4013f18" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_kbr_ComprehensiveIncomeLossNetOfTaxAttributableToNoncontrollingInterestDiscontinuedOperations_019e22aa-3ed8-77e7-abcd-4bd661c5d28e" xlink:href="kbr-20260703.xsd#kbr_ComprehensiveIncomeLossNetOfTaxAttributableToNoncontrollingInterestDiscontinuedOperations"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTax_019e22aa-3ed8-7a62-9254-6ef183663499" xlink:to="loc_kbr_ComprehensiveIncomeLossNetOfTaxAttributableToNoncontrollingInterestDiscontinuedOperations_019e22aa-3ed8-77e7-abcd-4bd661c5d28e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTax_019e22aa-3ed8-77b3-8b8d-f29ff7754ec3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeTax"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentBeforeTax_019e22aa-3ed8-7052-994f-03a428c6b7cc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentBeforeTax"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTax_019e22aa-3ed8-77b3-8b8d-f29ff7754ec3" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentBeforeTax_019e22aa-3ed8-7052-994f-03a428c6b7cc" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax_019e22aa-3ed8-71c6-80dc-58a6170058eb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTax_019e22aa-3ed8-77b3-8b8d-f29ff7754ec3" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax_019e22aa-3ed8-71c6-80dc-58a6170058eb" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTax_019e22aa-3ed8-706b-bd36-3a7b83e9856d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTax"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTax_019e22aa-3ed8-77b3-8b8d-f29ff7754ec3" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTax_019e22aa-3ed8-706b-bd36-3a7b83e9856d" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.kbr.com/role/CondensedConsolidatedBalanceSheets" xlink:type="simple" xlink:href="kbr-20260703.xsd#CondensedConsolidatedBalanceSheets"/>
  <link:calculationLink xlink:role="http://www.kbr.com/role/CondensedConsolidatedBalanceSheets" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_019e22aa-3ed8-73d5-aa89-f307f110f3e6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrent_019e22aa-3ed8-7307-90c9-9f611b143557" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableCurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019e22aa-3ed8-73d5-aa89-f307f110f3e6" xlink:to="loc_us-gaap_AccountsPayableCurrent_019e22aa-3ed8-7307-90c9-9f611b143557" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityCurrent_019e22aa-3ed8-7717-bdd1-7e27d92094e0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerLiabilityCurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019e22aa-3ed8-73d5-aa89-f307f110f3e6" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityCurrent_019e22aa-3ed8-7717-bdd1-7e27d92094e0" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_019e22aa-3ed8-7b42-b52b-8f49fe1d57ea" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019e22aa-3ed8-73d5-aa89-f307f110f3e6" xlink:to="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_019e22aa-3ed8-7b42-b52b-8f49fe1d57ea" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtCurrent_019e22aa-3ed8-7a2b-aece-975e9298cc7f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtCurrent"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019e22aa-3ed8-73d5-aa89-f307f110f3e6" xlink:to="loc_us-gaap_LongTermDebtCurrent_019e22aa-3ed8-7a2b-aece-975e9298cc7f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesCurrent_019e22aa-3ed8-7d61-ad92-28956f2fb306" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilitiesCurrent"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019e22aa-3ed8-73d5-aa89-f307f110f3e6" xlink:to="loc_us-gaap_OtherLiabilitiesCurrent_019e22aa-3ed8-7d61-ad92-28956f2fb306" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent_019e22aa-3ed8-7570-8621-bbd5a1e0e485" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019e22aa-3ed8-73d5-aa89-f307f110f3e6" xlink:to="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent_019e22aa-3ed8-7570-8621-bbd5a1e0e485" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_019e22aa-3ed8-7161-a4c4-af1375858c56" 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_AssetsCurrent_019e22aa-3ed8-7ee9-a7fb-4bb22c895140" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsCurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019e22aa-3ed8-7161-a4c4-af1375858c56" xlink:to="loc_us-gaap_AssetsCurrent_019e22aa-3ed8-7ee9-a7fb-4bb22c895140" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent_019e22aa-3ed8-7365-a588-aa9029ee9ffd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019e22aa-3ed8-7161-a4c4-af1375858c56" xlink:to="loc_us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent_019e22aa-3ed8-7365-a588-aa9029ee9ffd" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization_019e22aa-3ed8-7995-9f3d-69103ff68a6a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019e22aa-3ed8-7161-a4c4-af1375858c56" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization_019e22aa-3ed8-7995-9f3d-69103ff68a6a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_019e22aa-3ed8-7cdc-8cb6-9d9ceeb56dc5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019e22aa-3ed8-7161-a4c4-af1375858c56" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_019e22aa-3ed8-7cdc-8cb6-9d9ceeb56dc5" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_019e22aa-3ed8-7697-9e54-2293fea7a90e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Goodwill"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019e22aa-3ed8-7161-a4c4-af1375858c56" xlink:to="loc_us-gaap_Goodwill_019e22aa-3ed8-7697-9e54-2293fea7a90e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_019e22aa-3ed8-7b37-b207-2d3bb35e49c1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019e22aa-3ed8-7161-a4c4-af1375858c56" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_019e22aa-3ed8-7b37-b207-2d3bb35e49c1" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_019e22aa-3ed8-7f3a-9ac5-1a8f95b7fcfe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures"/>
    <link:calculationArc order="7" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019e22aa-3ed8-7161-a4c4-af1375858c56" xlink:to="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_019e22aa-3ed8-7f3a-9ac5-1a8f95b7fcfe" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxAssetsNet_019e22aa-3ed8-7284-9a61-6120ed34206f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredIncomeTaxAssetsNet"/>
    <link:calculationArc order="8" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019e22aa-3ed8-7161-a4c4-af1375858c56" xlink:to="loc_us-gaap_DeferredIncomeTaxAssetsNet_019e22aa-3ed8-7284-9a61-6120ed34206f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_019e22aa-3ed8-7a87-be0c-7a303b530abf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:calculationArc order="9" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019e22aa-3ed8-7161-a4c4-af1375858c56" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_019e22aa-3ed8-7a87-be0c-7a303b530abf" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e22aa-3ed8-7389-9df2-2df25a3e00b8" 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_PreferredStockValue_019e22aa-3ed8-77bf-897f-18496afcd18d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockValue"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_019e22aa-3ed8-7389-9df2-2df25a3e00b8" xlink:to="loc_us-gaap_PreferredStockValue_019e22aa-3ed8-77bf-897f-18496afcd18d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue_019e22aa-3ed8-7643-8249-4a94787a4972" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockValue"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_019e22aa-3ed8-7389-9df2-2df25a3e00b8" xlink:to="loc_us-gaap_CommonStockValue_019e22aa-3ed8-7643-8249-4a94787a4972" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapital_019e22aa-3ed8-7298-b400-c03210674a14" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapital"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_019e22aa-3ed8-7389-9df2-2df25a3e00b8" xlink:to="loc_us-gaap_AdditionalPaidInCapital_019e22aa-3ed8-7298-b400-c03210674a14" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_019e22aa-3ed8-7249-b108-2c0ba106431d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_019e22aa-3ed8-7389-9df2-2df25a3e00b8" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_019e22aa-3ed8-7249-b108-2c0ba106431d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_019e22aa-3ed8-74df-9169-3de489122db5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_019e22aa-3ed8-7389-9df2-2df25a3e00b8" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_019e22aa-3ed8-74df-9169-3de489122db5" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonValue_019e22aa-3ed8-7487-acfc-6c59d13f56f2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockCommonValue"/>
    <link:calculationArc order="6" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_019e22aa-3ed8-7389-9df2-2df25a3e00b8" xlink:to="loc_us-gaap_TreasuryStockCommonValue_019e22aa-3ed8-7487-acfc-6c59d13f56f2" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019e22aa-3ed8-7efc-aaa2-fe6853f6f4ad" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e22aa-3ed8-7b6f-a9f8-c8eae8befae8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019e22aa-3ed8-7efc-aaa2-fe6853f6f4ad" xlink:to="loc_us-gaap_StockholdersEquity_019e22aa-3ed8-7b6f-a9f8-c8eae8befae8" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterest_019e22aa-3ed8-7c63-b8e0-e06b2c3e2938" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MinorityInterest"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019e22aa-3ed8-7efc-aaa2-fe6853f6f4ad" xlink:to="loc_us-gaap_MinorityInterest_019e22aa-3ed8-7c63-b8e0-e06b2c3e2938" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_019e22aa-3ed8-7735-92a3-dd2ab8d12b09" 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_019e22aa-3ed8-770e-9073-2fd587cd39fd" 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_019e22aa-3ed8-7735-92a3-dd2ab8d12b09" xlink:to="loc_us-gaap_Liabilities_019e22aa-3ed8-770e-9073-2fd587cd39fd" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019e22aa-3ed8-789b-95c1-a896626222eb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_019e22aa-3ed8-7735-92a3-dd2ab8d12b09" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019e22aa-3ed8-789b-95c1-a896626222eb" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingencies_019e22aa-3ed8-7104-8ea0-87f2316ef153" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommitmentsAndContingencies"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_019e22aa-3ed8-7735-92a3-dd2ab8d12b09" xlink:to="loc_us-gaap_CommitmentsAndContingencies_019e22aa-3ed8-7104-8ea0-87f2316ef153" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_019e22aa-3ed8-7714-8b95-a4733e911f33" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsCurrent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019e22aa-3ed8-7e89-a60f-f482d5642d74" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019e22aa-3ed8-7714-8b95-a4733e911f33" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019e22aa-3ed8-7e89-a60f-f482d5642d74" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableNetCurrent_019e22aa-3ed8-7ba5-bcda-a4ae84e3ba2c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsNotesAndLoansReceivableNetCurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019e22aa-3ed8-7714-8b95-a4733e911f33" xlink:to="loc_us-gaap_AccountsNotesAndLoansReceivableNetCurrent_019e22aa-3ed8-7ba5-bcda-a4ae84e3ba2c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetNet_019e22aa-3ed8-760e-ac87-7a9c6dcdbdb8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerAssetNet"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019e22aa-3ed8-7714-8b95-a4733e911f33" xlink:to="loc_us-gaap_ContractWithCustomerAssetNet_019e22aa-3ed8-760e-ac87-7a9c6dcdbdb8" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsCurrent_019e22aa-3ed8-72f9-9e15-47bf2eb1f425" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssetsCurrent"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019e22aa-3ed8-7714-8b95-a4733e911f33" xlink:to="loc_us-gaap_OtherAssetsCurrent_019e22aa-3ed8-72f9-9e15-47bf2eb1f425" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent_019e22aa-3ed8-7e7b-baf4-0cf688dc87b7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019e22aa-3ed8-7714-8b95-a4733e911f33" xlink:to="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent_019e22aa-3ed8-7e7b-baf4-0cf688dc87b7" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_019e22aa-3ed8-7c83-93ea-9c35973c108f" 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_LiabilitiesCurrent_019e22aa-3ed8-78c9-98a6-9c815181477b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_019e22aa-3ed8-7c83-93ea-9c35973c108f" xlink:to="loc_us-gaap_LiabilitiesCurrent_019e22aa-3ed8-78c9-98a6-9c815181477b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_kbr_NoncurrentEmployeeCompensationAndBenefits_019e22aa-3ed8-790d-bbaf-4912b9cecad6" xlink:href="kbr-20260703.xsd#kbr_NoncurrentEmployeeCompensationAndBenefits"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_019e22aa-3ed8-7c83-93ea-9c35973c108f" xlink:to="loc_kbr_NoncurrentEmployeeCompensationAndBenefits_019e22aa-3ed8-790d-bbaf-4912b9cecad6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedIncomeTaxesNoncurrent_019e22aa-3ed8-774f-b2cc-ffeba87b4b0a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccruedIncomeTaxesNoncurrent"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_019e22aa-3ed8-7c83-93ea-9c35973c108f" xlink:to="loc_us-gaap_AccruedIncomeTaxesNoncurrent_019e22aa-3ed8-774f-b2cc-ffeba87b4b0a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_019e22aa-3ed8-7450-bfe1-4e9ac7212fbc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_019e22aa-3ed8-7c83-93ea-9c35973c108f" xlink:to="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_019e22aa-3ed8-7450-bfe1-4e9ac7212fbc" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_019e22aa-3ed8-7054-ba41-59400b86ca31" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtNoncurrent"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_019e22aa-3ed8-7c83-93ea-9c35973c108f" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_019e22aa-3ed8-7054-ba41-59400b86ca31" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_019e22aa-3ed8-71ea-b1be-05b8f99d2207" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_019e22aa-3ed8-7c83-93ea-9c35973c108f" xlink:to="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_019e22aa-3ed8-71ea-b1be-05b8f99d2207" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_019e22aa-3ed8-7183-b003-5753b1347272" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilitiesNoncurrent"/>
    <link:calculationArc order="7" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_019e22aa-3ed8-7c83-93ea-9c35973c108f" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_019e22aa-3ed8-7183-b003-5753b1347272" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.kbr.com/role/CondensedConsolidatedStatementsofCashFlows" xlink:type="simple" xlink:href="kbr-20260703.xsd#CondensedConsolidatedStatementsofCashFlows"/>
  <link:calculationLink xlink:role="http://www.kbr.com/role/CondensedConsolidatedStatementsofCashFlows" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_019e22aa-3ed8-77a6-8057-311fa2368794" 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_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_019e22aa-3ed8-7da1-a560-5e185aff242b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_019e22aa-3ed8-77a6-8057-311fa2368794" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_019e22aa-3ed8-7da1-a560-5e185aff242b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_019e22aa-3ed8-7f6a-aa69-87c7c8441496" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_019e22aa-3ed8-77a6-8057-311fa2368794" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_019e22aa-3ed8-7f6a-aa69-87c7c8441496" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_019e22aa-3ed8-7402-9249-5bea59be6b47" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_019e22aa-3ed8-77a6-8057-311fa2368794" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_019e22aa-3ed8-7402-9249-5bea59be6b47" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019e22aa-3ed8-7a5e-8047-cf45ef9c95a5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_019e22aa-3ed8-77a6-8057-311fa2368794" xlink:to="loc_us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019e22aa-3ed8-7a5e-8047-cf45ef9c95a5" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInDiscontinuedOperations_019e22aa-3ed8-7289-9349-5ab399103abc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInDiscontinuedOperations"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_019e22aa-3ed8-77a6-8057-311fa2368794" xlink:to="loc_us-gaap_NetCashProvidedByUsedInDiscontinuedOperations_019e22aa-3ed8-7289-9349-5ab399103abc" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_019e22aa-3ed8-73f9-82ce-4419c7ad84ca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromLinesOfCredit_019e22aa-3ed8-73b2-9c1c-992c9757c986" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromLinesOfCredit"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_019e22aa-3ed8-73f9-82ce-4419c7ad84ca" xlink:to="loc_us-gaap_ProceedsFromLinesOfCredit_019e22aa-3ed8-73b2-9c1c-992c9757c986" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfOtherLongTermDebt_019e22aa-3ed8-7a0f-b614-b6ee98abd0b9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RepaymentsOfOtherLongTermDebt"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_019e22aa-3ed8-73f9-82ce-4419c7ad84ca" xlink:to="loc_us-gaap_RepaymentsOfOtherLongTermDebt_019e22aa-3ed8-7a0f-b614-b6ee98abd0b9" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfLinesOfCredit_019e22aa-3ed8-7faa-bd89-9a37f4358b69" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RepaymentsOfLinesOfCredit"/>
    <link:calculationArc order="3" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_019e22aa-3ed8-73f9-82ce-4419c7ad84ca" xlink:to="loc_us-gaap_RepaymentsOfLinesOfCredit_019e22aa-3ed8-7faa-bd89-9a37f4358b69" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_019e22aa-3ed8-7909-a20a-a436841a4924" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsForRepurchaseOfCommonStock"/>
    <link:calculationArc order="4" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_019e22aa-3ed8-73f9-82ce-4419c7ad84ca" xlink:to="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_019e22aa-3ed8-7909-a20a-a436841a4924" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfDividendsCommonStock_019e22aa-3ed8-76e0-b603-c5e30b511462" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsOfDividendsCommonStock"/>
    <link:calculationArc order="5" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_019e22aa-3ed8-73f9-82ce-4419c7ad84ca" xlink:to="loc_us-gaap_PaymentsOfDividendsCommonStock_019e22aa-3ed8-76e0-b603-c5e30b511462" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromPaymentsForOtherFinancingActivities_019e22aa-3ed8-7938-a0d7-2e7f1987133c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromPaymentsForOtherFinancingActivities"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_019e22aa-3ed8-73f9-82ce-4419c7ad84ca" xlink:to="loc_us-gaap_ProceedsFromPaymentsForOtherFinancingActivities_019e22aa-3ed8-7938-a0d7-2e7f1987133c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations_019e22aa-3ed8-7e0f-9e63-bc9cf78c7e49" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsDisposalGroupIncludingDiscontinuedOperations_019e22aa-3ed8-73c1-b3b0-54e1c6ceb03f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsDisposalGroupIncludingDiscontinuedOperations"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations_019e22aa-3ed8-7e0f-9e63-bc9cf78c7e49" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsDisposalGroupIncludingDiscontinuedOperations_019e22aa-3ed8-73c1-b3b0-54e1c6ceb03f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019e22aa-3ed8-7eea-b8c8-6795a7267778" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations_019e22aa-3ed8-7e0f-9e63-bc9cf78c7e49" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019e22aa-3ed8-7eea-b8c8-6795a7267778" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_019e22aa-3ed8-75e2-a1cb-f287532d7636" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest_019e22aa-3ed8-7dc5-93de-c8d34ad9cda7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_019e22aa-3ed8-75e2-a1cb-f287532d7636" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest_019e22aa-3ed8-7dc5-93de-c8d34ad9cda7" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationAndAmortization_019e22aa-3ed8-7588-80b6-49f43d817379" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DepreciationAndAmortization"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_019e22aa-3ed8-75e2-a1cb-f287532d7636" xlink:to="loc_us-gaap_DepreciationAndAmortization_019e22aa-3ed8-7588-80b6-49f43d817379" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_019e22aa-3ed8-7f30-bf02-d1608bc90e44" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:calculationArc order="3" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_019e22aa-3ed8-75e2-a1cb-f287532d7636" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_019e22aa-3ed8-7f30-bf02-d1608bc90e44" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxesAndTaxCredits_019e22aa-3ed8-7ab5-a4ee-a7999d14ec1a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredIncomeTaxesAndTaxCredits"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_019e22aa-3ed8-75e2-a1cb-f287532d7636" xlink:to="loc_us-gaap_DeferredIncomeTaxesAndTaxCredits_019e22aa-3ed8-7ab5-a4ee-a7999d14ec1a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseImpairmentLoss_019e22aa-3ed8-7361-b353-725bf51fe3b7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseImpairmentLoss"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_019e22aa-3ed8-75e2-a1cb-f287532d7636" xlink:to="loc_us-gaap_OperatingLeaseImpairmentLoss_019e22aa-3ed8-7361-b353-725bf51fe3b7" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncashIncomeExpense_019e22aa-3ed8-70a5-810c-3a14e396198c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNoncashIncomeExpense"/>
    <link:calculationArc order="6" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_019e22aa-3ed8-75e2-a1cb-f287532d7636" xlink:to="loc_us-gaap_OtherNoncashIncomeExpense_019e22aa-3ed8-70a5-810c-3a14e396198c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_019e22aa-3ed8-7e97-a50d-91a3ffaec39a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable"/>
    <link:calculationArc order="7" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_019e22aa-3ed8-75e2-a1cb-f287532d7636" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_019e22aa-3ed8-7e97-a50d-91a3ffaec39a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInContractWithCustomerAsset_019e22aa-3ed8-79cf-aea5-20295382efbf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInContractWithCustomerAsset"/>
    <link:calculationArc order="8" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_019e22aa-3ed8-75e2-a1cb-f287532d7636" xlink:to="loc_us-gaap_IncreaseDecreaseInContractWithCustomerAsset_019e22aa-3ed8-79cf-aea5-20295382efbf" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayable_019e22aa-3ed8-7a19-8666-92727425c0df" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInAccountsPayable"/>
    <link:calculationArc order="9" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_019e22aa-3ed8-75e2-a1cb-f287532d7636" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayable_019e22aa-3ed8-7a19-8666-92727425c0df" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInContractWithCustomerLiability_019e22aa-3ed8-76e6-ba63-26fb90fc481c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInContractWithCustomerLiability"/>
    <link:calculationArc order="10" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_019e22aa-3ed8-75e2-a1cb-f287532d7636" xlink:to="loc_us-gaap_IncreaseDecreaseInContractWithCustomerLiability_019e22aa-3ed8-76e6-ba63-26fb90fc481c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_019e22aa-3ed8-7298-997b-9f12d53f3a9a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities"/>
    <link:calculationArc order="11" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_019e22aa-3ed8-75e2-a1cb-f287532d7636" xlink:to="loc_us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_019e22aa-3ed8-7298-997b-9f12d53f3a9a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeasePayments_019e22aa-3ed8-70a1-99f7-cbac0547b304" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeasePayments"/>
    <link:calculationArc order="12" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_019e22aa-3ed8-75e2-a1cb-f287532d7636" xlink:to="loc_us-gaap_OperatingLeasePayments_019e22aa-3ed8-70a1-99f7-cbac0547b304" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_kbr_CollectionsRepaymentOfAdvancesFromToUnconsolidatedAffiliatesNet_019e22aa-3ed8-7071-9ede-f9b34350f3a5" xlink:href="kbr-20260703.xsd#kbr_CollectionsRepaymentOfAdvancesFromToUnconsolidatedAffiliatesNet"/>
    <link:calculationArc order="13" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_019e22aa-3ed8-75e2-a1cb-f287532d7636" xlink:to="loc_kbr_CollectionsRepaymentOfAdvancesFromToUnconsolidatedAffiliatesNet_019e22aa-3ed8-7071-9ede-f9b34350f3a5" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentDividendsOrDistributions_019e22aa-3ed8-71e6-902d-b9014f2b106f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestmentDividendsOrDistributions"/>
    <link:calculationArc order="14" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_019e22aa-3ed8-75e2-a1cb-f287532d7636" xlink:to="loc_us-gaap_EquityMethodInvestmentDividendsOrDistributions_019e22aa-3ed8-71e6-902d-b9014f2b106f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssets_019f69e0-27a5-70b6-8a69-fd96e33fe5d7" 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_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_019e22aa-3ed8-75e2-a1cb-f287532d7636" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssets_019f69e0-27a5-70b6-8a69-fd96e33fe5d7" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_019e22aa-3ed8-7907-aa24-df2f8e1806b1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_019e22aa-3ed8-71a9-8855-93493e624aaa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_019e22aa-3ed8-7907-aa24-df2f8e1806b1" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_019e22aa-3ed8-71a9-8855-93493e624aaa" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital_019e22aa-3ed8-70a5-aa55-f575dfb6a786" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_019e22aa-3ed8-7907-aa24-df2f8e1806b1" xlink:to="loc_us-gaap_ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital_019e22aa-3ed8-70a5-aa55-f575dfb6a786" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_019e22aa-3ed8-7a4c-b375-c633fca9d526" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired"/>
    <link:calculationArc order="3" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_019e22aa-3ed8-7907-aa24-df2f8e1806b1" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_019e22aa-3ed8-7a4c-b375-c633fca9d526" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_019e22aa-3ed8-72ba-b552-aa2b88120011" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt"/>
    <link:calculationArc order="4" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_019e22aa-3ed8-7907-aa24-df2f8e1806b1" xlink:to="loc_us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_019e22aa-3ed8-72ba-b552-aa2b88120011" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireOtherInvestments_019e22aa-3ed8-71aa-a3af-5d1eb386d4b8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToAcquireOtherInvestments"/>
    <link:calculationArc order="5" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_019e22aa-3ed8-7907-aa24-df2f8e1806b1" xlink:to="loc_us-gaap_PaymentsToAcquireOtherInvestments_019e22aa-3ed8-71aa-a3af-5d1eb386d4b8" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForProceedsFromOtherInvestingActivities_019e647b-a2a5-7c5f-a418-4d50b404128b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsForProceedsFromOtherInvestingActivities"/>
    <link:calculationArc order="6" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_019e22aa-3ed8-7907-aa24-df2f8e1806b1" xlink:to="loc_us-gaap_PaymentsForProceedsFromOtherInvestingActivities_019e647b-a2a5-7c5f-a418-4d50b404128b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireEquityMethodInvestments_019f8fb6-7ddb-7632-ae23-e8d1651fbccb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToAcquireEquityMethodInvestments"/>
    <link:calculationArc order="7" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_019e22aa-3ed8-7907-aa24-df2f8e1806b1" xlink:to="loc_us-gaap_PaymentsToAcquireEquityMethodInvestments_019f8fb6-7ddb-7632-ae23-e8d1651fbccb" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInDiscontinuedOperations_019e22aa-3ed8-703f-8f13-c3f40fdc8b24" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInDiscontinuedOperations"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations_019e22aa-3ed8-7b9b-8237-e2f0ebcef9ca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInDiscontinuedOperations_019e22aa-3ed8-703f-8f13-c3f40fdc8b24" xlink:to="loc_us-gaap_CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations_019e22aa-3ed8-7b9b-8237-e2f0ebcef9ca" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations_019e22aa-3ed8-7b33-8b55-41da67cff281" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInDiscontinuedOperations_019e22aa-3ed8-703f-8f13-c3f40fdc8b24" xlink:to="loc_us-gaap_CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations_019e22aa-3ed8-7b33-8b55-41da67cff281" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations_019e647d-1688-774a-bdac-8933b4891033" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInDiscontinuedOperations_019e22aa-3ed8-703f-8f13-c3f40fdc8b24" xlink:to="loc_us-gaap_CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations_019e647d-1688-774a-bdac-8933b4891033" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.kbr.com/role/BusinessSegmentInformationScheduleofOperationsbyReportableSegmentDetails" xlink:type="simple" xlink:href="kbr-20260703.xsd#BusinessSegmentInformationScheduleofOperationsbyReportableSegmentDetails"/>
  <link:calculationLink xlink:role="http://www.kbr.com/role/BusinessSegmentInformationScheduleofOperationsbyReportableSegmentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperations_019e22aa-3ed8-7aea-bd37-02194418383b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperations"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest_019e22aa-3ed8-71c4-bb25-9dd60c1c04d4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperations_019e22aa-3ed8-7aea-bd37-02194418383b" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest_019e22aa-3ed8-71c4-bb25-9dd60c1c04d4" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsAttributableToNoncontrollingEntity_019e22aa-3ed8-7560-a852-8c86a8851462" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsAttributableToNoncontrollingEntity"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperations_019e22aa-3ed8-7aea-bd37-02194418383b" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsAttributableToNoncontrollingEntity_019e22aa-3ed8-7560-a852-8c86a8851462" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.kbr.com/role/RetirementBenefitsScheduleofNetPeriodicPensionBenefitDetails" xlink:type="simple" xlink:href="kbr-20260703.xsd#RetirementBenefitsScheduleofNetPeriodicPensionBenefitDetails"/>
  <link:calculationLink xlink:role="http://www.kbr.com/role/RetirementBenefitsScheduleofNetPeriodicPensionBenefitDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_019e22aa-40af-7b6c-a136-7dfc77f488bd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanInterestCost_019e22aa-40af-73e3-8aaf-d3bb9ea1c220" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanInterestCost"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_019e22aa-40af-7b6c-a136-7dfc77f488bd" xlink:to="loc_us-gaap_DefinedBenefitPlanInterestCost_019e22aa-40af-73e3-8aaf-d3bb9ea1c220" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_019e22aa-40af-7506-a9ae-0bbf58bfba3a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_019e22aa-40af-7b6c-a136-7dfc77f488bd" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_019e22aa-40af-7506-a9ae-0bbf58bfba3a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_019e67ee-42e0-70ce-b94b-cdad34ca910d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_019e22aa-40af-7b6c-a136-7dfc77f488bd" xlink:to="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_019e67ee-42e0-70ce-b94b-cdad34ca910d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_019e22aa-40af-77d9-a874-a1da2c23d31e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses"/>
    <link:calculationArc order="4" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_019e22aa-40af-7b6c-a136-7dfc77f488bd" xlink:to="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_019e22aa-40af-77d9-a874-a1da2c23d31e" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.kbr.com/role/DebtandOtherCreditFacilitiesScheduleofOutstandingDebtBalancesDetails" xlink:type="simple" xlink:href="kbr-20260703.xsd#DebtandOtherCreditFacilitiesScheduleofOutstandingDebtBalancesDetails"/>
  <link:calculationLink xlink:role="http://www.kbr.com/role/DebtandOtherCreditFacilitiesScheduleofOutstandingDebtBalancesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_019e22aa-40af-72ac-be31-de16315876d8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebt"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_019e22aa-40af-744d-84f6-840880253973" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LongTermDebt_019e22aa-40af-72ac-be31-de16315876d8" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_019e22aa-40af-744d-84f6-840880253973" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_019e22aa-40af-7783-a4da-151fb0588276" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredFinanceCostsNet"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LongTermDebt_019e22aa-40af-72ac-be31-de16315876d8" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_019e22aa-40af-7783-a4da-151fb0588276" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.kbr.com/role/DebtandOtherCreditFacilitiesScheduleofOutstandingDebtBalancesDetails_1" xlink:type="simple" xlink:href="kbr-20260703.xsd#DebtandOtherCreditFacilitiesScheduleofOutstandingDebtBalancesDetails_1"/>
  <link:calculationLink xlink:role="http://www.kbr.com/role/DebtandOtherCreditFacilitiesScheduleofOutstandingDebtBalancesDetails_1" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_019e22aa-40af-76db-ae26-d62d97bec867" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebt"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtCurrent_019e22aa-40af-75da-8ae7-8fc9b9519a9a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtCurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LongTermDebt_019e22aa-40af-76db-ae26-d62d97bec867" xlink:to="loc_us-gaap_LongTermDebtCurrent_019e22aa-40af-75da-8ae7-8fc9b9519a9a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_019e22aa-40af-74d7-b0dc-d5d351d8923b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtNoncurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LongTermDebt_019e22aa-40af-76db-ae26-d62d97bec867" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_019e22aa-40af-74d7-b0dc-d5d351d8923b" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.kbr.com/role/AccumulatedOtherComprehensiveLossScheduleofAccumulatedOtherComprehensiveIncomeLossDetails" xlink:type="simple" xlink:href="kbr-20260703.xsd#AccumulatedOtherComprehensiveLossScheduleofAccumulatedOtherComprehensiveIncomeLossDetails"/>
  <link:calculationLink xlink:role="http://www.kbr.com/role/AccumulatedOtherComprehensiveLossScheduleofAccumulatedOtherComprehensiveIncomeLossDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_019e22aa-40b0-725d-a61f-fc2c26c197de" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_019e22aa-40b0-7b12-9408-2f7f19d57afc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_019e22aa-40b0-725d-a61f-fc2c26c197de" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_019e22aa-40b0-7b12-9408-2f7f19d57afc" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_019e22aa-40b0-74f2-84ac-8e25cef07701" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_019e22aa-40b0-725d-a61f-fc2c26c197de" xlink:to="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_019e22aa-40b0-74f2-84ac-8e25cef07701" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.kbr.com/role/AccumulatedOtherComprehensiveLossScheduleofReclassificationOutofAccumulatedOtherComprehensiveIncomeDetails" xlink:type="simple" xlink:href="kbr-20260703.xsd#AccumulatedOtherComprehensiveLossScheduleofReclassificationOutofAccumulatedOtherComprehensiveIncomeDetails"/>
  <link:calculationLink xlink:role="http://www.kbr.com/role/AccumulatedOtherComprehensiveLossScheduleofReclassificationOutofAccumulatedOtherComprehensiveIncomeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_019e22aa-40b0-76cd-b5d0-0dbe64870d6b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProfitLoss"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_019e22aa-40b0-7cd9-ae38-02b5a7025cac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_ProfitLoss_019e22aa-40b0-76cd-b5d0-0dbe64870d6b" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_019e22aa-40b0-7cd9-ae38-02b5a7025cac" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_019e681e-c80b-76c3-8758-bc19bdc76d97" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_ProfitLoss_019e22aa-40b0-76cd-b5d0-0dbe64870d6b" xlink:to="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_019e681e-c80b-76c3-8758-bc19bdc76d97" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanActuarialGainLoss_019e22aa-40b0-7857-a284-3fdc202c23e1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanActuarialGainLoss"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_ProfitLoss_019e22aa-40b0-76cd-b5d0-0dbe64870d6b" xlink:to="loc_us-gaap_DefinedBenefitPlanActuarialGainLoss_019e22aa-40b0-7857-a284-3fdc202c23e1" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseNonoperating_019e22aa-40b0-788a-800b-9a952352f814" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseNonoperating"/>
    <link:calculationArc order="4" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_ProfitLoss_019e22aa-40b0-76cd-b5d0-0dbe64870d6b" xlink:to="loc_us-gaap_InterestExpenseNonoperating_019e22aa-40b0-788a-800b-9a952352f814" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.kbr.com/role/IncomeperShareScheduleOfBasicAndDilutedWeightedAverageCommonSharesOutstandingDetails" xlink:type="simple" xlink:href="kbr-20260703.xsd#IncomeperShareScheduleOfBasicAndDilutedWeightedAverageCommonSharesOutstandingDetails"/>
  <link:calculationLink xlink:role="http://www.kbr.com/role/IncomeperShareScheduleOfBasicAndDilutedWeightedAverageCommonSharesOutstandingDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity_019e22aa-40b0-768c-8f41-4a708d92236b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodNetOfTax_019e22aa-40b0-71e2-a11d-f1b67fe91fbc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodNetOfTax"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity_019e22aa-40b0-768c-8f41-4a708d92236b" xlink:to="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodNetOfTax_019e22aa-40b0-71e2-a11d-f1b67fe91fbc" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest_019e22aa-40b0-7b03-8d49-f855206e84b8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity_019e22aa-40b0-768c-8f41-4a708d92236b" xlink:to="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest_019e22aa-40b0-7b03-8d49-f855206e84b8" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersBasic_019e22aa-40b0-76b2-81a0-544e1c997024" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersBasic"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic_019e682a-c6da-7119-90c9-a0e2ea10af5d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersBasic_019e22aa-40b0-76b2-81a0-544e1c997024" xlink:to="loc_us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic_019e682a-c6da-7119-90c9-a0e2ea10af5d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperations_019e22aa-40b0-7a3a-a2ca-5600d6b25c1e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperations"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersBasic_019e22aa-40b0-76b2-81a0-544e1c997024" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperations_019e22aa-40b0-7a3a-a2ca-5600d6b25c1e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019eb5c7-2910-7dbe-aad1-5737534359de" 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_WeightedAverageNumberOfSharesOutstandingBasic_019eb5c7-2910-7b8a-979c-f5a50e97aad6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019eb5c7-2910-7dbe-aad1-5737534359de" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019eb5c7-2910-7b8a-979c-f5a50e97aad6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_019eb5c7-2910-73cc-898d-be4db6f45257" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019eb5c7-2910-7dbe-aad1-5737534359de" xlink:to="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_019eb5c7-2910-73cc-898d-be4db6f45257" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersDiluted_019e22aa-40b0-73d7-9eee-0a1ee88ede44" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersDiluted"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperations_019e22aa-40b0-7ed7-a541-9bd48b1c3002" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperations"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersDiluted_019e22aa-40b0-73d7-9eee-0a1ee88ede44" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperations_019e22aa-40b0-7ed7-a541-9bd48b1c3002" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.kbr.com/role/FairValueofFinancialInstrumentsandRiskManagementScheduleofChangesinFairValueofBalanceSheetHedgesDetails" xlink:type="simple" xlink:href="kbr-20260703.xsd#FairValueofFinancialInstrumentsandRiskManagementScheduleofChangesinFairValueofBalanceSheetHedgesDetails"/>
  <link:calculationLink xlink:role="http://www.kbr.com/role/FairValueofFinancialInstrumentsandRiskManagementScheduleofChangesinFairValueofBalanceSheetHedgesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnForeignCurrencyFairValueHedgeDerivatives_019e22aa-40b0-7ea8-b9d0-0ea963f85bd0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnForeignCurrencyFairValueHedgeDerivatives"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnFairValueHedgesRecognizedInEarnings_019e22aa-40b0-7864-92c4-aae57ee5b61a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnFairValueHedgesRecognizedInEarnings"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_GainLossOnForeignCurrencyFairValueHedgeDerivatives_019e22aa-40b0-7ea8-b9d0-0ea963f85bd0" xlink:to="loc_us-gaap_GainLossOnFairValueHedgesRecognizedInEarnings_019e22aa-40b0-7864-92c4-aae57ee5b61a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ChangeInUnrealizedGainLossOnHedgedItemInForeignCurrencyFairValueHedge1_019e22aa-40b0-784a-8463-61536e42c493" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ChangeInUnrealizedGainLossOnHedgedItemInForeignCurrencyFairValueHedge1"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_GainLossOnForeignCurrencyFairValueHedgeDerivatives_019e22aa-40b0-7ea8-b9d0-0ea963f85bd0" xlink:to="loc_us-gaap_ChangeInUnrealizedGainLossOnHedgedItemInForeignCurrencyFairValueHedge1_019e22aa-40b0-784a-8463-61536e42c493" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.kbr.com/role/DiscontinuedOperationsScheduleofComponentsofNetLossAttributabletoKBRFromDiscontinuedOperationsDetails" xlink:type="simple" xlink:href="kbr-20260703.xsd#DiscontinuedOperationsScheduleofComponentsofNetLossAttributabletoKBRFromDiscontinuedOperationsDetails"/>
  <link:calculationLink xlink:role="http://www.kbr.com/role/DiscontinuedOperationsScheduleofComponentsofNetLossAttributabletoKBRFromDiscontinuedOperationsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodBeforeIncomeTax_019e22aa-40b0-7de0-a673-57ec755e5048" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodBeforeIncomeTax"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss_019e22aa-40b0-7ac8-8906-71b2d47c522d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodBeforeIncomeTax_019e22aa-40b0-7de0-a673-57ec755e5048" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss_019e22aa-40b0-7ac8-8906-71b2d47c522d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationGrossProfitLoss_019e22aa-40b0-766a-b6d5-90ed7a45f6e8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationGrossProfitLoss"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue_019e22aa-40b0-7716-9537-ff7712ca5431" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationGrossProfitLoss_019e22aa-40b0-766a-b6d5-90ed7a45f6e8" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue_019e22aa-40b0-7716-9537-ff7712ca5431" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_kbr_DisposalGroupIncludingDiscontinuedOperationCostsOfGoodsSoldNetOfReserves_019e22aa-40b0-7703-8ed2-daf2c66707b0" xlink:href="kbr-20260703.xsd#kbr_DisposalGroupIncludingDiscontinuedOperationCostsOfGoodsSoldNetOfReserves"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationGrossProfitLoss_019e22aa-40b0-766a-b6d5-90ed7a45f6e8" xlink:to="loc_kbr_DisposalGroupIncludingDiscontinuedOperationCostsOfGoodsSoldNetOfReserves_019e22aa-40b0-7703-8ed2-daf2c66707b0" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss_019e22aa-40b0-7192-b9f8-1cae0372e96a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationGrossProfitLoss_019e22aa-40b0-7872-9bb0-f8627dd64842" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationGrossProfitLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss_019e22aa-40b0-7192-b9f8-1cae0372e96a" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationGrossProfitLoss_019e22aa-40b0-7872-9bb0-f8627dd64842" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_kbr_DisposalGroupIncludingDiscontinuedOperationGeneralAndAdministrativeExpenseNet_019e22aa-40b0-7e96-8949-9043a27174f9" xlink:href="kbr-20260703.xsd#kbr_DisposalGroupIncludingDiscontinuedOperationGeneralAndAdministrativeExpenseNet"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss_019e22aa-40b0-7192-b9f8-1cae0372e96a" xlink:to="loc_kbr_DisposalGroupIncludingDiscontinuedOperationGeneralAndAdministrativeExpenseNet_019e22aa-40b0-7e96-8949-9043a27174f9" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_kbr_DisposalGroupIncludingDiscontinuedOperationLossOnDisposal_019e683b-5569-7f26-8c81-9bf2236a1e8f" xlink:href="kbr-20260703.xsd#kbr_DisposalGroupIncludingDiscontinuedOperationLossOnDisposal"/>
    <link:calculationArc order="3" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss_019e22aa-40b0-7192-b9f8-1cae0372e96a" xlink:to="loc_kbr_DisposalGroupIncludingDiscontinuedOperationLossOnDisposal_019e683b-5569-7f26-8c81-9bf2236a1e8f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodNetOfTax_019e22aa-40b0-70f3-b649-c580d6a5f560" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodNetOfTax"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodBeforeIncomeTax_019e22aa-40b0-7d1c-aba0-8f7ad95477e1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodBeforeIncomeTax"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodNetOfTax_019e22aa-40b0-70f3-b649-c580d6a5f560" xlink:to="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodBeforeIncomeTax_019e22aa-40b0-7d1c-aba0-8f7ad95477e1" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DiscontinuedOperationTaxEffectOfIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriod_019e22aa-40b0-75a1-8ab3-2b8e5e77ef8e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DiscontinuedOperationTaxEffectOfIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriod"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodNetOfTax_019e22aa-40b0-70f3-b649-c580d6a5f560" xlink:to="loc_us-gaap_DiscontinuedOperationTaxEffectOfIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriod_019e22aa-40b0-75a1-8ab3-2b8e5e77ef8e" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.kbr.com/role/DiscontinuedOperationsScheduleofClassesofAssetsandLiabilitiesofDiscontinuedOperationsDetails" xlink:type="simple" xlink:href="kbr-20260703.xsd#DiscontinuedOperationsScheduleofClassesofAssetsandLiabilitiesofDiscontinuedOperationsDetails"/>
  <link:calculationLink xlink:role="http://www.kbr.com/role/DiscontinuedOperationsScheduleofClassesofAssetsandLiabilitiesofDiscontinuedOperationsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent_019e22aa-40b0-7919-bc51-edd909fef707" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationCashAndCashEquivalents_019e22aa-40b0-74b7-9b7b-6f77f6c175cb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationCashAndCashEquivalents"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent_019e22aa-40b0-7919-bc51-edd909fef707" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationCashAndCashEquivalents_019e22aa-40b0-74b7-9b7b-6f77f6c175cb" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationAccountsNotesAndLoansReceivableNet_019e22aa-40b0-79b3-9f2e-0ae0884802b7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationAccountsNotesAndLoansReceivableNet"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent_019e22aa-40b0-7919-bc51-edd909fef707" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationAccountsNotesAndLoansReceivableNet_019e22aa-40b0-79b3-9f2e-0ae0884802b7" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherCurrentAssets_019e22aa-40b0-70e1-abb6-cf6a209403bc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherCurrentAssets"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent_019e22aa-40b0-7919-bc51-edd909fef707" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherCurrentAssets_019e22aa-40b0-70e1-abb6-cf6a209403bc" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent_019e22aa-40b0-7895-876c-3c88c57dfff9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationAccountsPayableCurrent_019e22aa-40b0-769a-b538-ecc4527e3bf6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationAccountsPayableCurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent_019e22aa-40b0-7895-876c-3c88c57dfff9" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationAccountsPayableCurrent_019e22aa-40b0-769a-b538-ecc4527e3bf6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationDeferredRevenueCurrent_019e22aa-40b0-724f-9f7c-3e6b20d2df5f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationDeferredRevenueCurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent_019e22aa-40b0-7895-876c-3c88c57dfff9" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationDeferredRevenueCurrent_019e22aa-40b0-724f-9f7c-3e6b20d2df5f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_kbr_DisposalGroupIncludingDiscontinuedOperationAccruedSalariesWagesAndBenefits_019e22aa-40b0-78c4-899e-6f8fa54738dd" xlink:href="kbr-20260703.xsd#kbr_DisposalGroupIncludingDiscontinuedOperationAccruedSalariesWagesAndBenefits"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent_019e22aa-40b0-7895-876c-3c88c57dfff9" xlink:to="loc_kbr_DisposalGroupIncludingDiscontinuedOperationAccruedSalariesWagesAndBenefits_019e22aa-40b0-78c4-899e-6f8fa54738dd" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherCurrentLiabilities_019e22aa-40b0-7010-8ddf-ef4031cb238a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherCurrentLiabilities"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent_019e22aa-40b0-7895-876c-3c88c57dfff9" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherCurrentLiabilities_019e22aa-40b0-7010-8ddf-ef4031cb238a" xlink:type="arc"/>
  </link:calculationLink>
</link:linkbase>
