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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019e183b-29b0-7c69-9684-160e6dd3f21a,g:e866f93b-4e74-4031-95ad-6b572090f740-->
<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://atkore.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONS" xlink:type="simple" xlink:href="atkr-20260626.xsd#CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONS"/>
  <link:calculationLink xlink:role="http://atkore.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONS" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_019e183b-2b4d-712f-8265-964ca7fad386" 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_019e183b-2b4d-7087-97d8-9a6b430d2e8e" 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_019e183b-2b4d-712f-8265-964ca7fad386" xlink:to="loc_us-gaap_GrossProfit_019e183b-2b4d-7087-97d8-9a6b430d2e8e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_019e183b-2b4d-740a-bf0d-df398542e36e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AmortizationOfIntangibleAssets"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss_019e183b-2b4d-712f-8265-964ca7fad386" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_019e183b-2b4d-740a-bf0d-df398542e36e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_019e183b-2b4d-7e8d-a626-137f7e0be25c" 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_019e183b-2b4d-712f-8265-964ca7fad386" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_019e183b-2b4d-7e8d-a626-137f7e0be25c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetImpairmentCharges_019e183b-2b4d-73af-b06b-bbd2dc0920cd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetImpairmentCharges"/>
    <link:calculationArc order="4" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss_019e183b-2b4d-712f-8265-964ca7fad386" xlink:to="loc_us-gaap_AssetImpairmentCharges_019e183b-2b4d-73af-b06b-bbd2dc0920cd" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e183b-2b4d-7c6e-a73b-ae62ca3dfff1" 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_OperatingIncomeLoss_019e183b-2b4d-7510-8734-43812de9d746" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e183b-2b4d-7c6e-a73b-ae62ca3dfff1" xlink:to="loc_us-gaap_OperatingIncomeLoss_019e183b-2b4d-7510-8734-43812de9d746" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeExpenseNonoperatingNet_019e183b-2b4d-7f7d-bdf3-6cfae5a38271" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestIncomeExpenseNonoperatingNet"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e183b-2b4d-7c6e-a73b-ae62ca3dfff1" xlink:to="loc_us-gaap_InterestIncomeExpenseNonoperatingNet_019e183b-2b4d-7f7d-bdf3-6cfae5a38271" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationSettlementExpense_019e183b-2b4d-79ed-be2e-113e817a09a7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LitigationSettlementExpense"/>
    <link:calculationArc order="3" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e183b-2b4d-7c6e-a73b-ae62ca3dfff1" xlink:to="loc_us-gaap_LitigationSettlementExpense_019e183b-2b4d-79ed-be2e-113e817a09a7" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_019e183b-2b4d-7c46-98a3-96b2d04c46c2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e183b-2b4d-7c6e-a73b-ae62ca3dfff1" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_019e183b-2b4d-7c46-98a3-96b2d04c46c2" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GrossProfit_019e183b-2b4d-7331-8b62-e8ca321df4f2" 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_RevenueFromContractWithCustomerExcludingAssessedTax_019e183b-2b4d-76ac-a27c-973084c1b1e0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_GrossProfit_019e183b-2b4d-7331-8b62-e8ca321df4f2" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e183b-2b4d-76ac-a27c-973084c1b1e0" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_019e183b-2b4d-7797-b651-a0dbc76d0dac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_GrossProfit_019e183b-2b4d-7331-8b62-e8ca321df4f2" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_019e183b-2b4d-7797-b651-a0dbc76d0dac" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019e183b-2b4d-7d5f-843b-4c8e36851b3b" 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_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e183b-2b4d-7819-99e5-262f0c4f99a9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss_019e183b-2b4d-7d5f-843b-4c8e36851b3b" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e183b-2b4d-7819-99e5-262f0c4f99a9" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_019e183b-2b4d-74f1-a849-f6fd82b12868" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss_019e183b-2b4d-7d5f-843b-4c8e36851b3b" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_019e183b-2b4d-74f1-a849-f6fd82b12868" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://atkore.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOME" xlink:type="simple" xlink:href="atkr-20260626.xsd#CONDENSEDCONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOME"/>
  <link:calculationLink xlink:role="http://atkore.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOME" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019e183b-2b4d-7cb6-bbfa-35643615bfb7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent_019e183b-2b4d-7a9d-94e4-a78be5c6726a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019e183b-2b4d-7cb6-bbfa-35643615bfb7" xlink:to="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent_019e183b-2b4d-7a9d-94e4-a78be5c6726a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_019e183b-2b4d-7765-b0c8-e376c2373d09" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019e183b-2b4d-7cb6-bbfa-35643615bfb7" xlink:to="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_019e183b-2b4d-7765-b0c8-e376c2373d09" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_019e183b-2b4d-7586-b0c1-1046e3659107" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ComprehensiveIncomeNetOfTax"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019e183b-2b4d-70a1-9a6d-02b015b2444d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTax_019e183b-2b4d-7586-b0c1-1046e3659107" xlink:to="loc_us-gaap_NetIncomeLoss_019e183b-2b4d-70a1-9a6d-02b015b2444d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019e183b-2b4d-74d7-8bab-94b0782e39ad" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTax_019e183b-2b4d-7586-b0c1-1046e3659107" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019e183b-2b4d-74d7-8bab-94b0782e39ad" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://atkore.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETS" xlink:type="simple" xlink:href="atkr-20260626.xsd#CONDENSEDCONSOLIDATEDBALANCESHEETS"/>
  <link:calculationLink xlink:role="http://atkore.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETS" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_019e183b-2b4d-7e1e-b89d-dabb6b07189f" 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_atkr_OperatingAndFinanceLeaseLiabilityNoncurrent_019e183b-2b4d-7945-9152-aa89719e1e88" xlink:href="atkr-20260626.xsd#atkr_OperatingAndFinanceLeaseLiabilityNoncurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_019e183b-2b4d-7e1e-b89d-dabb6b07189f" xlink:to="loc_atkr_OperatingAndFinanceLeaseLiabilityNoncurrent_019e183b-2b4d-7945-9152-aa89719e1e88" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_019e183b-2b4d-77dc-8bf0-af0a7b5f8a7a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_019e183b-2b4d-7e1e-b89d-dabb6b07189f" xlink:to="loc_us-gaap_LiabilitiesCurrent_019e183b-2b4d-77dc-8bf0-af0a7b5f8a7a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_019e183b-2b4d-7426-aa35-f106e97dc0f5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtNoncurrent"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_019e183b-2b4d-7e1e-b89d-dabb6b07189f" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_019e183b-2b4d-7426-aa35-f106e97dc0f5" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_019e183b-2b4d-7219-beef-e9adbe0f9af6" 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_019e183b-2b4d-7e1e-b89d-dabb6b07189f" xlink:to="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_019e183b-2b4d-7219-beef-e9adbe0f9af6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_019e183b-2b4d-7b02-8e15-66f711848e97" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilitiesNoncurrent"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_019e183b-2b4d-7e1e-b89d-dabb6b07189f" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_019e183b-2b4d-7b02-8e15-66f711848e97" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_019e183b-2b4d-7be2-8e2d-6d78f53ee79a" 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_AccountsReceivableNetCurrent_019e183b-2b4d-7e9b-92bd-9f7cfbe4556b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019e183b-2b4d-7be2-8e2d-6d78f53ee79a" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_019e183b-2b4d-7e9b-92bd-9f7cfbe4556b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryNet_019e183b-2b4d-7566-9f7c-f515a3087c3b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryNet"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019e183b-2b4d-7be2-8e2d-6d78f53ee79a" xlink:to="loc_us-gaap_InventoryNet_019e183b-2b4d-7566-9f7c-f515a3087c3b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019e183b-2b4d-73d2-88b5-58f7bd1cc2ea" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019e183b-2b4d-7be2-8e2d-6d78f53ee79a" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019e183b-2b4d-73d2-88b5-58f7bd1cc2ea" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_019e183b-2b4d-77bd-8700-d455d60d946a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019e183b-2b4d-7be2-8e2d-6d78f53ee79a" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_019e183b-2b4d-77bd-8700-d455d60d946a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxesReceivable_019e183b-2b4d-7dc3-acd9-1b901b413ca4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxesReceivable"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_019e183b-2b4d-7be2-8e2d-6d78f53ee79a" xlink:to="loc_us-gaap_IncomeTaxesReceivable_019e183b-2b4d-7dc3-acd9-1b901b413ca4" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_019e183b-2b4d-7360-a039-7500f61f72ae" 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_LongTermDebtCurrent_019e183b-2b4d-75eb-9802-7bfc864c4743" 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_LiabilitiesCurrent_019e183b-2b4d-7360-a039-7500f61f72ae" xlink:to="loc_us-gaap_LongTermDebtCurrent_019e183b-2b4d-75eb-9802-7bfc864c4743" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrent_019e183b-2b4d-7b1b-925b-fd260f0dad2d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableCurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019e183b-2b4d-7360-a039-7500f61f72ae" xlink:to="loc_us-gaap_AccountsPayableCurrent_019e183b-2b4d-7b1b-925b-fd260f0dad2d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedIncomeTaxesCurrent_019e183b-2b4d-7ff3-b3ae-9e13265735ab" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccruedIncomeTaxesCurrent"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019e183b-2b4d-7360-a039-7500f61f72ae" xlink:to="loc_us-gaap_AccruedIncomeTaxesCurrent_019e183b-2b4d-7ff3-b3ae-9e13265735ab" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_019e183b-2b4d-79d2-80ec-5b2a98057322" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019e183b-2b4d-7360-a039-7500f61f72ae" xlink:to="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_019e183b-2b4d-79d2-80ec-5b2a98057322" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityCurrent_019e183b-2b4d-76c9-bbfa-a54cccd04a85" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerLiabilityCurrent"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019e183b-2b4d-7360-a039-7500f61f72ae" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityCurrent_019e183b-2b4d-76c9-bbfa-a54cccd04a85" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_atkr_OperatingAndFinanceLeaseLiabilityCurrent_019e183b-2b4d-75f5-95af-779737029c9b" xlink:href="atkr-20260626.xsd#atkr_OperatingAndFinanceLeaseLiabilityCurrent"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019e183b-2b4d-7360-a039-7500f61f72ae" xlink:to="loc_atkr_OperatingAndFinanceLeaseLiabilityCurrent_019e183b-2b4d-75f5-95af-779737029c9b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationReserveCurrent_019e183b-2b4d-7ec5-9626-15ba7bb079b9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LitigationReserveCurrent"/>
    <link:calculationArc order="7" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019e183b-2b4d-7360-a039-7500f61f72ae" xlink:to="loc_us-gaap_LitigationReserveCurrent_019e183b-2b4d-7ec5-9626-15ba7bb079b9" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesCurrent_019f7d6b-1bd2-7924-ab33-cf0e9eef8601" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilitiesCurrent"/>
    <link:calculationArc order="8" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_019e183b-2b4d-7360-a039-7500f61f72ae" xlink:to="loc_us-gaap_OtherLiabilitiesCurrent_019f7d6b-1bd2-7924-ab33-cf0e9eef8601" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e183b-2b4d-7b9c-83c4-6088abf02c31" 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_RetainedEarningsAccumulatedDeficit_019e183b-2b4d-7e88-819c-1be896773f0c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_019e183b-2b4d-7b9c-83c4-6088abf02c31" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_019e183b-2b4d-7e88-819c-1be896773f0c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalCommonStock_019e183b-2b4d-7da3-8bc2-9ee5c98025f5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapitalCommonStock"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_019e183b-2b4d-7b9c-83c4-6088abf02c31" xlink:to="loc_us-gaap_AdditionalPaidInCapitalCommonStock_019e183b-2b4d-7da3-8bc2-9ee5c98025f5" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue_019e183b-2b4d-7978-83ca-03ac72b44bc7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockValue"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_019e183b-2b4d-7b9c-83c4-6088abf02c31" xlink:to="loc_us-gaap_CommonStockValue_019e183b-2b4d-7978-83ca-03ac72b44bc7" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_019e183b-2b4d-7656-b3da-abad7d8df5be" 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_019e183b-2b4d-7b9c-83c4-6088abf02c31" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_019e183b-2b4d-7656-b3da-abad7d8df5be" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_019e183b-2b4d-7201-9f4e-ed4948cd3957" 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_019e183b-2b4d-7722-8a96-f4c961284bc7" 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_019e183b-2b4d-7201-9f4e-ed4948cd3957" xlink:to="loc_us-gaap_AssetsCurrent_019e183b-2b4d-7722-8a96-f4c961284bc7" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_019e183b-2b4d-72c7-a4c6-77e5ab2c7268" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019e183b-2b4d-7201-9f4e-ed4948cd3957" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_019e183b-2b4d-72c7-a4c6-77e5ab2c7268" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_019e183b-2b4d-7750-afa1-f85a64919da6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019e183b-2b4d-7201-9f4e-ed4948cd3957" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_019e183b-2b4d-7750-afa1-f85a64919da6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_019e183b-2b4d-72fd-a7ea-a40a4429a658" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Goodwill"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019e183b-2b4d-7201-9f4e-ed4948cd3957" xlink:to="loc_us-gaap_Goodwill_019e183b-2b4d-72fd-a7ea-a40a4429a658" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_atkr_OperatingAndFinanceLeaseRightOfUseAssetNet_019e183b-2b4d-7ae1-affa-bf27375acc6d" xlink:href="atkr-20260626.xsd#atkr_OperatingAndFinanceLeaseRightOfUseAssetNet"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019e183b-2b4d-7201-9f4e-ed4948cd3957" xlink:to="loc_atkr_OperatingAndFinanceLeaseRightOfUseAssetNet_019e183b-2b4d-7ae1-affa-bf27375acc6d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxAssetsNet_019e183b-2b4d-77ab-8eb3-e6948d0bb5bd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredIncomeTaxAssetsNet"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019e183b-2b4d-7201-9f4e-ed4948cd3957" xlink:to="loc_us-gaap_DeferredIncomeTaxAssetsNet_019e183b-2b4d-77ab-8eb3-e6948d0bb5bd" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestments_019e183b-2b4d-7ed9-89c6-15b79844ff0a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestments"/>
    <link:calculationArc order="7" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019e183b-2b4d-7201-9f4e-ed4948cd3957" xlink:to="loc_us-gaap_EquityMethodInvestments_019e183b-2b4d-7ed9-89c6-15b79844ff0a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_019f5b38-966e-7fd2-adb2-835c101f6628" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:calculationArc order="8" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_019e183b-2b4d-7201-9f4e-ed4948cd3957" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_019f5b38-966e-7fd2-adb2-835c101f6628" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_019e183b-2b4d-7725-b764-ac7b7c6ebd58" 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_019e183b-2b4d-7fa7-ac16-83407c78796f" 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_019e183b-2b4d-7725-b764-ac7b7c6ebd58" xlink:to="loc_us-gaap_Liabilities_019e183b-2b4d-7fa7-ac16-83407c78796f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e183b-2b4d-701d-b905-53c6d0a8ecd0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_019e183b-2b4d-7725-b764-ac7b7c6ebd58" xlink:to="loc_us-gaap_StockholdersEquity_019e183b-2b4d-701d-b905-53c6d0a8ecd0" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://atkore.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWS" xlink:type="simple" xlink:href="atkr-20260626.xsd#CONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWS"/>
  <link:calculationLink xlink:role="http://atkore.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWS" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_019e183b-2b4d-78b2-b383-ef8e51fbcc2f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e183b-2b4d-7ac2-aed5-c86a345fbca5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_019e183b-2b4d-78b2-b383-ef8e51fbcc2f" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e183b-2b4d-7ac2-aed5-c86a345fbca5" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019e183b-2b4d-71bc-a2b4-4db03214e648" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_019e183b-2b4d-78b2-b383-ef8e51fbcc2f" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019e183b-2b4d-71bc-a2b4-4db03214e648" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019e183b-2b4d-76c0-aa7e-9f00f138f853" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_019e183b-2b4d-78b2-b383-ef8e51fbcc2f" xlink:to="loc_us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019e183b-2b4d-76c0-aa7e-9f00f138f853" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019e183b-2b4d-7dd0-a29d-a13d8120c65b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_019e183b-2b4d-78b2-b383-ef8e51fbcc2f" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019e183b-2b4d-7dd0-a29d-a13d8120c65b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019e183b-2b4d-7552-90ed-6ab5bd7c96d0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfLongTermDebt_019e183b-2b4d-7771-be0b-6b31fccfb64f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RepaymentsOfLongTermDebt"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019e183b-2b4d-7552-90ed-6ab5bd7c96d0" xlink:to="loc_us-gaap_RepaymentsOfLongTermDebt_019e183b-2b4d-7771-be0b-6b31fccfb64f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentOfFinancingAndStockIssuanceCosts_019e183b-2b4d-7cf9-b03a-bd76fa218d1f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentOfFinancingAndStockIssuanceCosts"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019e183b-2b4d-7552-90ed-6ab5bd7c96d0" xlink:to="loc_us-gaap_PaymentOfFinancingAndStockIssuanceCosts_019e183b-2b4d-7cf9-b03a-bd76fa218d1f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_019e183b-2b4d-749d-ac65-80b44b852ac7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019e183b-2b4d-7552-90ed-6ab5bd7c96d0" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_019e183b-2b4d-749d-ac65-80b44b852ac7" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_019e183b-2b4d-7d8b-bae1-82b2a5e6bfa8" 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_NetCashProvidedByUsedInFinancingActivities_019e183b-2b4d-7552-90ed-6ab5bd7c96d0" xlink:to="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_019e183b-2b4d-7d8b-bae1-82b2a5e6bfa8" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeasePrincipalPayments_019e183b-2b4d-7fa6-8687-601e8c6567a9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinanceLeasePrincipalPayments"/>
    <link:calculationArc order="5" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019e183b-2b4d-7552-90ed-6ab5bd7c96d0" xlink:to="loc_us-gaap_FinanceLeasePrincipalPayments_019e183b-2b4d-7fa6-8687-601e8c6567a9" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfOrdinaryDividends_019e3e04-c863-7931-bbe7-c142ce5f376b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsOfOrdinaryDividends"/>
    <link:calculationArc order="6" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019e183b-2b4d-7552-90ed-6ab5bd7c96d0" xlink:to="loc_us-gaap_PaymentsOfOrdinaryDividends_019e3e04-c863-7931-bbe7-c142ce5f376b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019e183b-2b4d-7479-857e-d376360f46f5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_019e183b-2b4d-723e-8dd0-beda68128fe1" 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_NetCashProvidedByUsedInInvestingActivities_019e183b-2b4d-7479-857e-d376360f46f5" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_019e183b-2b4d-723e-8dd0-beda68128fe1" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromDivestitureOfBusinesses_019e183b-2b4d-7b96-92ac-d7ce6e8d0d89" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromDivestitureOfBusinesses"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019e183b-2b4d-7479-857e-d376360f46f5" xlink:to="loc_us-gaap_ProceedsFromDivestitureOfBusinesses_019e183b-2b4d-7b96-92ac-d7ce6e8d0d89" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_019e183b-2b4d-7705-8ee8-371bc2d04756" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019e183b-2b4d-7479-857e-d376360f46f5" xlink:to="loc_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_019e183b-2b4d-7705-8ee8-371bc2d04756" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromInsuranceSettlementInvestingActivities_019e183b-2b4d-7432-aafa-fff667b8466e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromInsuranceSettlementInvestingActivities"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019e183b-2b4d-7479-857e-d376360f46f5" xlink:to="loc_us-gaap_ProceedsFromInsuranceSettlementInvestingActivities_019e183b-2b4d-7432-aafa-fff667b8466e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireEquityMethodInvestments_019e3dfc-2ed0-756b-aa1a-8ee409ed3163" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToAcquireEquityMethodInvestments"/>
    <link:calculationArc order="5" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019e183b-2b4d-7479-857e-d376360f46f5" xlink:to="loc_us-gaap_PaymentsToAcquireEquityMethodInvestments_019e3dfc-2ed0-756b-aa1a-8ee409ed3163" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e183b-2b4d-7e90-900b-28c70c585362" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019e183b-2b4d-797c-9f91-e5297e808ba6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e183b-2b4d-7e90-900b-28c70c585362" xlink:to="loc_us-gaap_NetIncomeLoss_019e183b-2b4d-797c-9f91-e5297e808ba6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_019e183b-2b4d-70e8-a0e9-d76e53270aa0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DepreciationDepletionAndAmortization"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e183b-2b4d-7e90-900b-28c70c585362" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_019e183b-2b4d-70e8-a0e9-d76e53270aa0" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxExpenseBenefit_019e183b-2b4d-7121-8a4b-086098f7840a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredIncomeTaxExpenseBenefit"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e183b-2b4d-7e90-900b-28c70c585362" xlink:to="loc_us-gaap_DeferredIncomeTaxExpenseBenefit_019e183b-2b4d-7121-8a4b-086098f7840a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetImpairmentCharges_019e183b-2b4d-759f-8e7c-cca2325632c0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetImpairmentCharges"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e183b-2b4d-7e90-900b-28c70c585362" xlink:to="loc_us-gaap_AssetImpairmentCharges_019e183b-2b4d-759f-8e7c-cca2325632c0" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfBusiness_019e183b-2b4d-7317-b5d3-8f1c1b7ebc29" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnSaleOfBusiness"/>
    <link:calculationArc order="5" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e183b-2b4d-7e90-900b-28c70c585362" xlink:to="loc_us-gaap_GainLossOnSaleOfBusiness_019e183b-2b4d-7317-b5d3-8f1c1b7ebc29" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal_019e183b-2b4d-7897-8d4a-aaf608a93d3c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal"/>
    <link:calculationArc order="6" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e183b-2b4d-7e90-900b-28c70c585362" xlink:to="loc_us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal_019e183b-2b4d-7897-8d4a-aaf608a93d3c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensation_019e183b-2b4d-7d0e-89bb-e5e52a7713f4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensation"/>
    <link:calculationArc order="7" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e183b-2b4d-7e90-900b-28c70c585362" xlink:to="loc_us-gaap_ShareBasedCompensation_019e183b-2b4d-7d0e-89bb-e5e52a7713f4" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseRightOfUseAssetAmortization_019e183b-2b4d-773d-aec7-69185f187440" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinanceLeaseRightOfUseAssetAmortization"/>
    <link:calculationArc order="8" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e183b-2b4d-7e90-900b-28c70c585362" xlink:to="loc_us-gaap_FinanceLeaseRightOfUseAssetAmortization_019e183b-2b4d-773d-aec7-69185f187440" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_atkr_ProvisionForDoubtfulAccountsAndInventory_019e183b-2b4d-7948-8292-5f7791b923e6" xlink:href="atkr-20260626.xsd#atkr_ProvisionForDoubtfulAccountsAndInventory"/>
    <link:calculationArc order="9" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e183b-2b4d-7e90-900b-28c70c585362" xlink:to="loc_atkr_ProvisionForDoubtfulAccountsAndInventory_019e183b-2b4d-7948-8292-5f7791b923e6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherOperatingActivitiesCashFlowStatement_019e183b-2b4d-7784-ad29-32ad4a105322" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherOperatingActivitiesCashFlowStatement"/>
    <link:calculationArc order="10" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e183b-2b4d-7e90-900b-28c70c585362" xlink:to="loc_us-gaap_OtherOperatingActivitiesCashFlowStatement_019e183b-2b4d-7784-ad29-32ad4a105322" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_019e183b-2b4d-7347-9817-15d026246f00" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable"/>
    <link:calculationArc order="11" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e183b-2b4d-7e90-900b-28c70c585362" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_019e183b-2b4d-7347-9817-15d026246f00" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInInventories_019e183b-2b4d-7a82-856d-5207ee0c7d75" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInInventories"/>
    <link:calculationArc order="12" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e183b-2b4d-7e90-900b-28c70c585362" xlink:to="loc_us-gaap_IncreaseDecreaseInInventories_019e183b-2b4d-7a82-856d-5207ee0c7d75" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_019e183b-2b4d-7821-989e-86edf26fa437" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets"/>
    <link:calculationArc order="13" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e183b-2b4d-7e90-900b-28c70c585362" xlink:to="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_019e183b-2b4d-7821-989e-86edf26fa437" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayable_019e183b-2b4d-7f8e-924e-1378d22cdb22" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInAccountsPayable"/>
    <link:calculationArc order="14" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e183b-2b4d-7e90-900b-28c70c585362" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayable_019e183b-2b4d-7f8e-924e-1378d22cdb22" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_atkr_IncreaseDecreaseInLegalSettlementExpense_019e183b-2b4d-73a5-a09c-324b556d3b16" xlink:href="atkr-20260626.xsd#atkr_IncreaseDecreaseInLegalSettlementExpense"/>
    <link:calculationArc order="15" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e183b-2b4d-7e90-900b-28c70c585362" xlink:to="loc_atkr_IncreaseDecreaseInLegalSettlementExpense_019e183b-2b4d-73a5-a09c-324b556d3b16" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherAccruedLiabilities_019e183b-2b4d-71eb-a3bb-c7edfebfed92" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInOtherAccruedLiabilities"/>
    <link:calculationArc order="16" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e183b-2b4d-7e90-900b-28c70c585362" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherAccruedLiabilities_019e183b-2b4d-71eb-a3bb-c7edfebfed92" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_atkr_IncreaseDecreaseInLeaseAssetsAndLiabilities_019e183b-2b4d-7772-adf4-36774d11069d" xlink:href="atkr-20260626.xsd#atkr_IncreaseDecreaseInLeaseAssetsAndLiabilities"/>
    <link:calculationArc order="17" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e183b-2b4d-7e90-900b-28c70c585362" xlink:to="loc_atkr_IncreaseDecreaseInLeaseAssetsAndLiabilities_019e183b-2b4d-7772-adf4-36774d11069d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable_019e183b-2b4d-7b6e-994f-fed18f340347" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable"/>
    <link:calculationArc order="18" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e183b-2b4d-7e90-900b-28c70c585362" xlink:to="loc_us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable_019e183b-2b4d-7b6e-994f-fed18f340347" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_019f7d6b-e833-77e0-af78-f6e000daaa57" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet"/>
    <link:calculationArc order="19" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e183b-2b4d-7e90-900b-28c70c585362" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_019f7d6b-e833-77e0-af78-f6e000daaa57" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://atkore.com/role/DIVESTITURESScheduleofConsiderationreceivedDetails" xlink:type="simple" xlink:href="atkr-20260626.xsd#DIVESTITURESScheduleofConsiderationreceivedDetails"/>
  <link:calculationLink xlink:role="http://atkore.com/role/DIVESTITURESScheduleofConsiderationreceivedDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentsFairValueDisclosure_019f7d8c-bc8d-7894-86a0-39a855019ed3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestmentsFairValueDisclosure"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestments_019f7d8c-bc8d-70ba-90c6-b595c4090302" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestments"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_EquityMethodInvestmentsFairValueDisclosure_019f7d8c-bc8d-7894-86a0-39a855019ed3" xlink:to="loc_us-gaap_EquityMethodInvestments_019f7d8c-bc8d-70ba-90c6-b595c4090302" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_atkr_EquityMethodInvestmentAdditionalCommittedAmountCashProvidedAtClosing_019f7d8c-bc8d-724a-9ac0-050e91d64d45" xlink:href="atkr-20260626.xsd#atkr_EquityMethodInvestmentAdditionalCommittedAmountCashProvidedAtClosing"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_EquityMethodInvestmentsFairValueDisclosure_019f7d8c-bc8d-7894-86a0-39a855019ed3" xlink:to="loc_atkr_EquityMethodInvestmentAdditionalCommittedAmountCashProvidedAtClosing_019f7d8c-bc8d-724a-9ac0-050e91d64d45" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_atkr_EquityMethodInvestmentAdditionalCommittedAmountCashPayableAtClosing_019f7d8c-bc8d-788e-887c-f5efcfc79e56" xlink:href="atkr-20260626.xsd#atkr_EquityMethodInvestmentAdditionalCommittedAmountCashPayableAtClosing"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_EquityMethodInvestmentsFairValueDisclosure_019f7d8c-bc8d-7894-86a0-39a855019ed3" xlink:to="loc_atkr_EquityMethodInvestmentAdditionalCommittedAmountCashPayableAtClosing_019f7d8c-bc8d-788e-887c-f5efcfc79e56" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration_019f7d8c-977c-70be-b697-dfb973c36e72" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration"/>
    <link:loc xlink:type="locator" xlink:label="loc_atkr_DisposalGroupIncludingDiscontinuedOperationEquityMethodInvestmentReceived_019f7d8c-977c-7727-a699-e47a4e1abe5f" xlink:href="atkr-20260626.xsd#atkr_DisposalGroupIncludingDiscontinuedOperationEquityMethodInvestmentReceived"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration_019f7d8c-977c-70be-b697-dfb973c36e72" xlink:to="loc_atkr_DisposalGroupIncludingDiscontinuedOperationEquityMethodInvestmentReceived_019f7d8c-977c-7727-a699-e47a4e1abe5f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_atkr_DisposalGroupIncludingDiscontinuedOperationEarnoutDerivative_019f7d8c-977c-72b0-b538-4188eddf18a5" xlink:href="atkr-20260626.xsd#atkr_DisposalGroupIncludingDiscontinuedOperationEarnoutDerivative"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration_019f7d8c-977c-70be-b697-dfb973c36e72" xlink:to="loc_atkr_DisposalGroupIncludingDiscontinuedOperationEarnoutDerivative_019f7d8c-977c-72b0-b538-4188eddf18a5" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://atkore.com/role/POSTRETIREMENTBENEFITSDetails" xlink:type="simple" xlink:href="atkr-20260626.xsd#POSTRETIREMENTBENEFITSDetails"/>
  <link:calculationLink xlink:role="http://atkore.com/role/POSTRETIREMENTBENEFITSDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_019e183b-2b4d-7469-8ec0-017b6bd66e6c" 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_DefinedBenefitPlanExpectedReturnOnPlanAssets_019e183b-2b4d-7a09-8abd-317dbdc7f9ea" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_019e183b-2b4d-7469-8ec0-017b6bd66e6c" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_019e183b-2b4d-7a09-8abd-317dbdc7f9ea" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_019e183b-2b4d-7ca7-82d1-7048f9b9412c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_019e183b-2b4d-7469-8ec0-017b6bd66e6c" xlink:to="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_019e183b-2b4d-7ca7-82d1-7048f9b9412c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanInterestCost_019e183b-2b4d-7ab1-a065-630bb5fd2632" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanInterestCost"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_019e183b-2b4d-7469-8ec0-017b6bd66e6c" xlink:to="loc_us-gaap_DefinedBenefitPlanInterestCost_019e183b-2b4d-7ab1-a065-630bb5fd2632" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://atkore.com/role/OTHEREXPENSEINCOMENETScheduleofOtherExpenseIncomeNetDetails" xlink:type="simple" xlink:href="atkr-20260626.xsd#OTHEREXPENSEINCOMENETScheduleofOtherExpenseIncomeNetDetails"/>
  <link:calculationLink xlink:role="http://atkore.com/role/OTHEREXPENSEINCOMENETScheduleofOtherExpenseIncomeNetDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_019e183b-2b4d-7749-a9ec-b3b2f0770348" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal_019e183b-2b4d-7bb5-836a-054e0f201339" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherNonoperatingIncomeExpense_019e183b-2b4d-7749-a9ec-b3b2f0770348" xlink:to="loc_us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal_019e183b-2b4d-7bb5-836a-054e0f201339" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_atkr_ForeignExchangeGainLossOnIntercompanyLoans_019e183b-2b4d-7e0c-bf7c-1029fbd6ab46" xlink:href="atkr-20260626.xsd#atkr_ForeignExchangeGainLossOnIntercompanyLoans"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherNonoperatingIncomeExpense_019e183b-2b4d-7749-a9ec-b3b2f0770348" xlink:to="loc_atkr_ForeignExchangeGainLossOnIntercompanyLoans_019e183b-2b4d-7e0c-bf7c-1029fbd6ab46" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionExpense_019e183b-2b4d-79a7-8cf0-624fff4364c6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PensionExpense"/>
    <link:calculationArc order="3" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherNonoperatingIncomeExpense_019e183b-2b4d-7749-a9ec-b3b2f0770348" xlink:to="loc_us-gaap_PensionExpense_019e183b-2b4d-79a7-8cf0-624fff4364c6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfBusiness_019e183b-2b4d-75aa-bd5a-2b847b243698" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnSaleOfBusiness"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherNonoperatingIncomeExpense_019e183b-2b4d-7749-a9ec-b3b2f0770348" xlink:to="loc_us-gaap_GainLossOnSaleOfBusiness_019e183b-2b4d-75aa-bd5a-2b847b243698" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://atkore.com/role/EARNINGSPERSHAREDetails" xlink:type="simple" xlink:href="atkr-20260626.xsd#EARNINGSPERSHAREDetails"/>
  <link:calculationLink xlink:role="http://atkore.com/role/EARNINGSPERSHAREDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019e183b-2b4d-7acd-ac77-4c1c64d84d51" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019e183b-2b4d-7739-abd0-8cd670788ca4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019e183b-2b4d-7acd-ac77-4c1c64d84d51" xlink:to="loc_us-gaap_NetIncomeLoss_019e183b-2b4d-7739-abd0-8cd670788ca4" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic_019e183b-2b4d-7149-9a62-ab4fdd46642e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019e183b-2b4d-7acd-ac77-4c1c64d84d51" xlink:to="loc_us-gaap_UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic_019e183b-2b4d-7149-9a62-ab4fdd46642e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019e183b-2b4d-74bc-8163-d3ca3138d672" 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_019e183b-2b4d-7b84-a876-1d8570432840" 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_019e183b-2b4d-74bc-8163-d3ca3138d672" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019e183b-2b4d-7b84-a876-1d8570432840" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_019e183b-2b4d-7add-9c28-4244d8b7b167" 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_019e183b-2b4d-74bc-8163-d3ca3138d672" xlink:to="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_019e183b-2b4d-7add-9c28-4244d8b7b167" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://atkore.com/role/ACCUMULATEDOTHERCOMPREHENSIVELOSSDetails" xlink:type="simple" xlink:href="atkr-20260626.xsd#ACCUMULATEDOTHERCOMPREHENSIVELOSSDetails"/>
  <link:calculationLink xlink:role="http://atkore.com/role/ACCUMULATEDOTHERCOMPREHENSIVELOSSDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019e183b-2b4d-79ab-89e6-65846dc567d2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OciBeforeReclassificationsBeforeTaxAttributableToParent_019e183b-2b4d-72d9-b692-0774278a23e6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OciBeforeReclassificationsBeforeTaxAttributableToParent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019e183b-2b4d-79ab-89e6-65846dc567d2" xlink:to="loc_us-gaap_OciBeforeReclassificationsBeforeTaxAttributableToParent_019e183b-2b4d-72d9-b692-0774278a23e6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent_019e183b-2b4d-7709-ab2e-517aa0326ab3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019e183b-2b4d-79ab-89e6-65846dc567d2" xlink:to="loc_us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent_019e183b-2b4d-7709-ab2e-517aa0326ab3" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://atkore.com/role/INVENTORIESNETScheduleofCompanyInventoriesDetails" xlink:type="simple" xlink:href="atkr-20260626.xsd#INVENTORIESNETScheduleofCompanyInventoriesDetails"/>
  <link:calculationLink xlink:role="http://atkore.com/role/INVENTORIESNETScheduleofCompanyInventoriesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryNet_019e183b-2b4d-789f-a2aa-51b069e3376b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryNet"/>
    <link:loc xlink:type="locator" xlink:label="loc_atkr_InventoryRawMaterialsAndPurchasedPartsNetOfValuationReserves_019e183b-2b4d-7c33-9bf4-9d5578af2c4b" xlink:href="atkr-20260626.xsd#atkr_InventoryRawMaterialsAndPurchasedPartsNetOfValuationReserves"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_InventoryNet_019e183b-2b4d-789f-a2aa-51b069e3376b" xlink:to="loc_atkr_InventoryRawMaterialsAndPurchasedPartsNetOfValuationReserves_019e183b-2b4d-7c33-9bf4-9d5578af2c4b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryWorkInProcessNetOfReserves_019e183b-2b4d-7b3c-8c5d-6b84649d122f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryWorkInProcessNetOfReserves"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_InventoryNet_019e183b-2b4d-789f-a2aa-51b069e3376b" xlink:to="loc_us-gaap_InventoryWorkInProcessNetOfReserves_019e183b-2b4d-7b3c-8c5d-6b84649d122f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryFinishedGoodsNetOfReserves_019e183b-2b4d-7a92-b1dd-eeeda047f34e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryFinishedGoodsNetOfReserves"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_InventoryNet_019e183b-2b4d-789f-a2aa-51b069e3376b" xlink:to="loc_us-gaap_InventoryFinishedGoodsNetOfReserves_019e183b-2b4d-7a92-b1dd-eeeda047f34e" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://atkore.com/role/PROPERTYPLANTANDEQUIPMENTScheduleofPropertyPlantandEquipmentDetails" xlink:type="simple" xlink:href="atkr-20260626.xsd#PROPERTYPLANTANDEQUIPMENTScheduleofPropertyPlantandEquipmentDetails"/>
  <link:calculationLink xlink:role="http://atkore.com/role/PROPERTYPLANTANDEQUIPMENTScheduleofPropertyPlantandEquipmentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_019e183b-2c15-70e3-a6c8-b85d53df1655" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_019e183b-2c15-7617-8cc0-9e93bd6e0e97" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentGross"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNet_019e183b-2c15-70e3-a6c8-b85d53df1655" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_019e183b-2c15-7617-8cc0-9e93bd6e0e97" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_019e183b-2c15-77a6-be5c-e0fe581fe090" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNet_019e183b-2c15-70e3-a6c8-b85d53df1655" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_019e183b-2c15-77a6-be5c-e0fe581fe090" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://atkore.com/role/GOODWILLANDINTANGIBLEASSETSIntangibleAssetsDetails" xlink:type="simple" xlink:href="atkr-20260626.xsd#GOODWILLANDINTANGIBLEASSETSIntangibleAssetsDetails"/>
  <link:calculationLink xlink:role="http://atkore.com/role/GOODWILLANDINTANGIBLEASSETSIntangibleAssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_019e183b-2c15-7454-894e-fac4517c8f27" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_019e183b-2c15-7537-92d2-1be923352290" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_019e183b-2c15-7454-894e-fac4517c8f27" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_019e183b-2c15-7537-92d2-1be923352290" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_019e183b-2c15-722f-935e-855036636339" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_019e183b-2c15-7454-894e-fac4517c8f27" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_019e183b-2c15-722f-935e-855036636339" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsGrossExcludingGoodwill_019e183b-2c15-739c-b383-654cbd27cd45" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IntangibleAssetsGrossExcludingGoodwill"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_019e183b-2c15-70e2-8cd6-08e36382fe73" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IntangibleAssetsGrossExcludingGoodwill_019e183b-2c15-739c-b383-654cbd27cd45" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_019e183b-2c15-70e2-8cd6-08e36382fe73" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_019e183b-2c15-7ec5-b5d9-a8240b89846b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IntangibleAssetsGrossExcludingGoodwill_019e183b-2c15-739c-b383-654cbd27cd45" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_019e183b-2c15-7ec5-b5d9-a8240b89846b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_019e183b-2c15-7e50-9e70-c2ad5f1af985" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_019e183b-2c15-79b3-94c6-453c069a4c73" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNet_019e183b-2c15-7e50-9e70-c2ad5f1af985" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_019e183b-2c15-79b3-94c6-453c069a4c73" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_019e183b-2c15-72cf-b15d-b6016d8be4c7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNet_019e183b-2c15-7e50-9e70-c2ad5f1af985" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_019e183b-2c15-72cf-b15d-b6016d8be4c7" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://atkore.com/role/DEBTScheduleofDebtDetails" xlink:type="simple" xlink:href="atkr-20260626.xsd#DEBTScheduleofDebtDetails"/>
  <link:calculationLink xlink:role="http://atkore.com/role/DEBTScheduleofDebtDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_019e183b-2c15-70b1-8e33-0d3b085a4a70" 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_019e183b-2c15-7fa5-a204-4be2a63803f5" 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_019e183b-2c15-70b1-8e33-0d3b085a4a70" xlink:to="loc_us-gaap_LongTermDebtCurrent_019e183b-2c15-7fa5-a204-4be2a63803f5" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_019e183b-2c15-75cd-b314-c37ae50bb54c" 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_019e183b-2c15-70b1-8e33-0d3b085a4a70" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_019e183b-2c15-75cd-b314-c37ae50bb54c" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://atkore.com/role/DEBTScheduleofDebtDetails_1" xlink:type="simple" xlink:href="atkr-20260626.xsd#DEBTScheduleofDebtDetails_1"/>
  <link:calculationLink xlink:role="http://atkore.com/role/DEBTScheduleofDebtDetails_1" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_019e183b-2c15-78ec-bddc-82c2afffe8d1" 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_atkr_LongTermDebtNetOfUnamortizedDiscount_019e183b-2c15-7bb8-9774-1c43f8c7f742" xlink:href="atkr-20260626.xsd#atkr_LongTermDebtNetOfUnamortizedDiscount"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LongTermDebt_019e183b-2c15-78ec-bddc-82c2afffe8d1" xlink:to="loc_atkr_LongTermDebtNetOfUnamortizedDiscount_019e183b-2c15-7bb8-9774-1c43f8c7f742" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_019e183b-2c15-7d26-b954-20f22f017b18" 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_019e183b-2c15-78ec-bddc-82c2afffe8d1" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_019e183b-2c15-7d26-b954-20f22f017b18" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://atkore.com/role/SEGMENTINFORMATIONReconciliationofOperatingSegmentIncomeDetails" xlink:type="simple" xlink:href="atkr-20260626.xsd#SEGMENTINFORMATIONReconciliationofOperatingSegmentIncomeDetails"/>
  <link:calculationLink xlink:role="http://atkore.com/role/SEGMENTINFORMATIONReconciliationofOperatingSegmentIncomeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e183b-2c15-7e78-bb93-109aa9c3d595" 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_atkr_IncomeLossFromContinuingOperationsAdjustedEarningsBeforeInterestTaxesDepreciationAndAmortizationEBITDA_019e183b-2c15-7431-bd65-e6b50006795c" xlink:href="atkr-20260626.xsd#atkr_IncomeLossFromContinuingOperationsAdjustedEarningsBeforeInterestTaxesDepreciationAndAmortizationEBITDA"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e183b-2c15-7e78-bb93-109aa9c3d595" xlink:to="loc_atkr_IncomeLossFromContinuingOperationsAdjustedEarningsBeforeInterestTaxesDepreciationAndAmortizationEBITDA_019e183b-2c15-7431-bd65-e6b50006795c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_atkr_SellingGeneralAndAdministrativeExpenseUnallocated_019e183b-2c15-7aa9-99c3-1caae24a3056" xlink:href="atkr-20260626.xsd#atkr_SellingGeneralAndAdministrativeExpenseUnallocated"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e183b-2c15-7e78-bb93-109aa9c3d595" xlink:to="loc_atkr_SellingGeneralAndAdministrativeExpenseUnallocated_019e183b-2c15-7aa9-99c3-1caae24a3056" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_019e183b-2c15-7762-9506-f80ee61eb018" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DepreciationDepletionAndAmortization"/>
    <link:calculationArc order="3" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e183b-2c15-7e78-bb93-109aa9c3d595" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_019e183b-2c15-7762-9506-f80ee61eb018" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeExpenseNonoperatingNet_019e183b-2c15-7c07-b151-114bdf2e2fe3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestIncomeExpenseNonoperatingNet"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e183b-2c15-7e78-bb93-109aa9c3d595" xlink:to="loc_us-gaap_InterestIncomeExpenseNonoperatingNet_019e183b-2c15-7c07-b151-114bdf2e2fe3" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfBusiness_019e183b-2c15-726f-aa46-51b22e790ba6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnSaleOfBusiness"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e183b-2c15-7e78-bb93-109aa9c3d595" xlink:to="loc_us-gaap_GainLossOnSaleOfBusiness_019e183b-2c15-726f-aa46-51b22e790ba6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetImpairmentCharges_019e183b-2c15-79d2-8723-8d9a9ea47b06" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetImpairmentCharges"/>
    <link:calculationArc order="6" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e183b-2c15-7e78-bb93-109aa9c3d595" xlink:to="loc_us-gaap_AssetImpairmentCharges_019e183b-2c15-79d2-8723-8d9a9ea47b06" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_019e183b-2c15-7d25-8907-2f1ea624321b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:calculationArc order="7" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e183b-2c15-7e78-bb93-109aa9c3d595" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_019e183b-2c15-7d25-8907-2f1ea624321b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherOperatingIncomeExpenseNet_019e183b-2c15-7daa-af36-246001b31f83" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherOperatingIncomeExpenseNet"/>
    <link:calculationArc order="8" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e183b-2c15-7e78-bb93-109aa9c3d595" xlink:to="loc_us-gaap_OtherOperatingIncomeExpenseNet_019e183b-2c15-7daa-af36-246001b31f83" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_atkr_TransactionCosts_019e183b-2c15-7c15-bffe-4ba902659ba8" xlink:href="atkr-20260626.xsd#atkr_TransactionCosts"/>
    <link:calculationArc order="9" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e183b-2c15-7e78-bb93-109aa9c3d595" xlink:to="loc_atkr_TransactionCosts_019e183b-2c15-7c15-bffe-4ba902659ba8" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_atkr_GainLossOnAssetsHeldForSale_019e183b-2c15-7fcd-9741-ee806ccdc817" xlink:href="atkr-20260626.xsd#atkr_GainLossOnAssetsHeldForSale"/>
    <link:calculationArc order="10" weight="1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e183b-2c15-7e78-bb93-109aa9c3d595" xlink:to="loc_atkr_GainLossOnAssetsHeldForSale_019e183b-2c15-7fcd-9741-ee806ccdc817" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCharges_019e183b-2c15-7f31-ae3e-03296a76d7c5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestructuringCharges"/>
    <link:calculationArc order="11" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e183b-2c15-7e78-bb93-109aa9c3d595" xlink:to="loc_us-gaap_RestructuringCharges_019e183b-2c15-7f31-ae3e-03296a76d7c5" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationSettlementExpense_019e183b-2c15-7b8c-8e7c-2b1cac58861f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LitigationSettlementExpense"/>
    <link:calculationArc order="12" weight="-1.0" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e183b-2c15-7e78-bb93-109aa9c3d595" xlink:to="loc_us-gaap_LitigationSettlementExpense_019e183b-2c15-7b8c-8e7c-2b1cac58861f" xlink:type="arc"/>
  </link:calculationLink>
</link:linkbase>
