MaxGhenis · Oct 11, 2026
diff --git a/changelog.d/ks-itemized-deductions-closed-list.fixed.md b/changelog.d/ks-itemized-deductions-closed-list.fixed.md
@@ -0,0 +1 @@
+Limit Kansas itemized deductions to charitable contributions, medical care, qualified residence interest and property taxes at the K.S.A. 79-32,120(a) shares for each year, and require federal itemizing before 2021.
diff --git a/...parameters/gov/states/ks/tax/income/deductions/itemized/federal_itemization_required.yaml b/...parameters/gov/states/ks/tax/income/deductions/itemized/federal_itemization_required.yaml
@@ -0,0 +1,13 @@
+description: Kansas allows the Kansas itemized deduction only to filers who itemize on their federal return, if this is true.
+values:
+  2015-01-01: true
+  2021-01-01: false
+metadata:
+  unit: bool
+  period: year
+  label: Kansas itemized deduction requires federal itemization
+  reference:
+    - title: K.S.A. 79-32,120(a)(1)
+      href: https://www.ksrevisor.gov/statutes/chapters/ch79/079_032_0120.html
+    - title: 2018 Form K-40 instructions, itemized deductions
+      href: https://www.ksrevenue.gov/pdf/ip18.pdf#page=2
diff --git a/...arameters/gov/states/ks/tax/income/deductions/itemized/rate/charitable_contributions.yaml b/...arameters/gov/states/ks/tax/income/deductions/itemized/rate/charitable_contributions.yaml
@@ -0,0 +1,14 @@
+description: Kansas allows this share of charitable contributions deductible under section 170 of the Internal Revenue Code as an itemized deduction.
+values:
+  2015-01-01: 1
+metadata:
+  unit: /1
+  period: year
+  label: Kansas itemized deduction share of charitable contributions
+  reference:
+    - title: K.S.A. 79-32,120(a)
+      href: https://www.ksrevisor.gov/statutes/chapters/ch79/079_032_0120.html
+    - title: 2017 Form K-40 instructions, Schedule S Part C, line C4
+      href: https://www.ksrevenue.gov/pdf/ip17.pdf#page=14
+    - title: 2025 Form K-40 instructions, Kansas Schedule A
+      href: https://www.ksrevenue.gov/pdf/ip25.pdf#page=14
diff --git a/...ine_us/parameters/gov/states/ks/tax/income/deductions/itemized/rate/medical_expenses.yaml b/...ine_us/parameters/gov/states/ks/tax/income/deductions/itemized/rate/medical_expenses.yaml
@@ -0,0 +1,19 @@
+description: Kansas allows this share of medical expenses deductible under section 213 of the Internal Revenue Code as an itemized deduction.
+values:
+  2015-01-01: 0
+  2018-01-01: 0.5
+  2019-01-01: 0.75
+  2020-01-01: 1
+metadata:
+  unit: /1
+  period: year
+  label: Kansas itemized deduction share of medical expenses
+  reference:
+    - title: K.S.A. 79-32,120(a)
+      href: https://www.ksrevisor.gov/statutes/chapters/ch79/079_032_0120.html
+    - title: 2018 Form K-40 instructions, itemized deductions
+      href: https://www.ksrevenue.gov/pdf/ip18.pdf#page=2
+    - title: 2019 Form K-40 instructions, itemized deductions
+      href: https://www.ksrevenue.gov/pdf/ip19.pdf#page=2
+    - title: 2025 Form K-40 instructions, Kansas Schedule A, lines 1 to 4
+      href: https://www.ksrevenue.gov/pdf/ip25.pdf#page=14
diff --git a/...ngine_us/parameters/gov/states/ks/tax/income/deductions/itemized/rate/property_taxes.yaml b/...ngine_us/parameters/gov/states/ks/tax/income/deductions/itemized/rate/property_taxes.yaml
@@ -0,0 +1,18 @@
+description: Kansas allows this share of taxes on real and personal property under section 164(a) of the Internal Revenue Code as an itemized deduction.
+values:
+  2015-01-01: 0.5
+  2019-01-01: 0.75
+  2020-01-01: 1
+metadata:
+  unit: /1
+  period: year
+  label: Kansas itemized deduction share of real and personal property taxes
+  reference:
+    - title: K.S.A. 79-32,120(a)
+      href: https://www.ksrevisor.gov/statutes/chapters/ch79/079_032_0120.html
+    - title: 2017 Form K-40 instructions, Schedule S Part C, lines C1 and C2
+      href: https://www.ksrevenue.gov/pdf/ip17.pdf#page=14
+    - title: 2018 Form K-40 instructions, itemized deductions
+      href: https://www.ksrevenue.gov/pdf/ip18.pdf#page=2
+    - title: 2019 Form K-40 instructions, itemized deductions
+      href: https://www.ksrevenue.gov/pdf/ip19.pdf#page=2
diff --git a/...eters/gov/states/ks/tax/income/deductions/itemized/rate/qualified_residence_interest.yaml b/...eters/gov/states/ks/tax/income/deductions/itemized/rate/qualified_residence_interest.yaml
@@ -0,0 +1,18 @@
+description: Kansas allows this share of qualified residence interest under section 163(h) of the Internal Revenue Code as an itemized deduction.
+values:
+  2015-01-01: 0.5
+  2019-01-01: 0.75
+  2020-01-01: 1
+metadata:
+  unit: /1
+  period: year
+  label: Kansas itemized deduction share of qualified residence interest
+  reference:
+    - title: K.S.A. 79-32,120(a)
+      href: https://www.ksrevisor.gov/statutes/chapters/ch79/079_032_0120.html
+    - title: 2017 Form K-40 instructions, Schedule S Part C, lines C3
+      href: https://www.ksrevenue.gov/pdf/ip17.pdf#page=14
+    - title: 2018 Form K-40 instructions, itemized deductions
+      href: https://www.ksrevenue.gov/pdf/ip18.pdf#page=2
+    - title: 2019 Form K-40 instructions, itemized deductions
+      href: https://www.ksrevenue.gov/pdf/ip19.pdf#page=2
diff --git a/policyengine_us/tests/policy/baseline/gov/states/ks/tax/income/ks_itemized_deductions.yaml b/policyengine_us/tests/policy/baseline/gov/states/ks/tax/income/ks_itemized_deductions.yaml
@@ -3,7 +3,7 @@
   input:
     real_estate_taxes: 8
     salt_deduction: 10
-    interest_deduction: 9
+    deductible_mortgage_interest_tax_unit: 9
     medical_expense_deduction: 2
     state_code: KS
   output:
@@ -14,8 +14,79 @@
   input:
     real_estate_taxes: 12
     salt_deduction: 10
-    interest_deduction: 9
+    deductible_mortgage_interest_tax_unit: 9
     medical_expense_deduction: 2
     state_code: KS
   output:
     ks_itemized_deductions: 12 + 9 + 2
+
+# K.S.A. 79-32,120(a)(5): from 2020, 100% of charitable contributions, medical
+# care, qualified residence interest and real and personal property taxes.
+# Investment interest and casualty losses are not Kansas itemized deductions.
+- name: Case 3, 2025 only the four Kansas categories count.
+  period: 2025
+  input:
+    state_code: KS
+    charitable_deduction: 3_000
+    medical_expense_deduction: 2_000
+    deductible_mortgage_interest_tax_unit: 9_000
+    interest_deduction: 13_000
+    casualty_loss_deduction: 1_000
+    real_estate_taxes: 5_000
+  output:
+    # 3,000 + 2,000 + 9,000 + 5,000; not the 4,000 of investment interest in
+    # interest_deduction or the 1,000 casualty loss.
+    ks_itemized_deductions: 19_000
+
+# K.S.A. 79-32,120(a)(4): 2019 allows 100% of charity and 75% of the other
+# three categories.
+- name: Case 4, 2019 shares.
+  period: 2019
+  input:
+    state_code: KS
+    charitable_deduction: 1_000
+    medical_expense_deduction: 2_000
+    deductible_mortgage_interest_tax_unit: 8_000
+    real_estate_taxes: 4_000
+  output:
+    # 1,000 + 0.75 * (2,000 + 8,000 + 4,000)
+    ks_itemized_deductions: 11_500
+
+# K.S.A. 79-32,120(a)(3): 2018 allows 100% of charity and 50% of the other
+# three categories.
+- name: Case 5, 2018 shares.
+  period: 2018
+  input:
+    state_code: KS
+    charitable_deduction: 1_000
+    medical_expense_deduction: 2_000
+    deductible_mortgage_interest_tax_unit: 8_000
+    real_estate_taxes: 4_000
+  output:
+    # 1,000 + 0.5 * (2,000 + 8,000 + 4,000)
+    ks_itemized_deductions: 8_000
+
+# K.S.A. 79-32,120(a)(2): 2015 to 2017 allow 100% of charity, 50% of qualified
+# residence interest and property taxes, and no medical care (2017 Schedule S,
+# Part C).
+- name: Case 6, 2017 shares, no medical expenses.
+  period: 2017
+  input:
+    state_code: KS
+    charitable_deduction: 1_000
+    medical_expense_deduction: 2_000
+    deductible_mortgage_interest_tax_unit: 8_000
+    real_estate_taxes: 4_000
+  output:
+    # 1,000 + 0.5 * (8,000 + 4,000)
+    ks_itemized_deductions: 7_000
+
+- name: Case 7, 2021 federal deduction for non-itemizers' charitable gifts is not a Kansas itemized deduction.
+  period: 2021
+  input:
+    state_code: KS
+    charitable_deduction: 2_000
+    charitable_deduction_for_non_itemizers: 300
+    real_estate_taxes: 4_000
+  output:
+    ks_itemized_deductions: 6_000
diff --git a/policyengine_us/tests/policy/baseline/gov/states/ks/tax/income/ks_taxable_income.yaml b/policyengine_us/tests/policy/baseline/gov/states/ks/tax/income/ks_taxable_income.yaml
@@ -30,3 +30,41 @@
     state_code: KS
   output:
     ks_taxable_income: 0
+
+# K.S.A. 79-32,120(a)(1)(A): before 2021, only federal itemizers may take the
+# Kansas itemized deduction; (a)(1)(B) removes that condition from 2021.
+- name: Case 4, 2019 non-itemizer federally takes the Kansas standard deduction.
+  period: 2019
+  input:
+    ks_agi: 50_000
+    ks_standard_deduction: 3_000
+    ks_itemized_deductions: 9_000
+    ks_exemptions: 2_250
+    tax_unit_itemizes: false
+    state_code: KS
+  output:
+    ks_taxable_income: 50_000 - 3_000 - 2_250
+
+- name: Case 5, 2019 federal itemizer takes the larger Kansas itemized deduction.
+  period: 2019
+  input:
+    ks_agi: 50_000
+    ks_standard_deduction: 3_000
+    ks_itemized_deductions: 9_000
+    ks_exemptions: 2_250
+    tax_unit_itemizes: true
+    state_code: KS
+  output:
+    ks_taxable_income: 50_000 - 9_000 - 2_250
+
+- name: Case 6, 2021 Kansas itemizing no longer requires federal itemizing.
+  period: 2021
+  input:
+    ks_agi: 50_000
+    ks_standard_deduction: 3_500
+    ks_itemized_deductions: 9_000
+    ks_exemptions: 2_250
+    tax_unit_itemizes: false
+    state_code: KS
+  output:
+    ks_taxable_income: 50_000 - 9_000 - 2_250
diff --git a/policyengine_us/variables/gov/states/ks/tax/income/deductions/ks_itemized_deductions.py b/policyengine_us/variables/gov/states/ks/tax/income/deductions/ks_itemized_deductions.py
@@ -8,21 +8,28 @@ class ks_itemized_deductions(Variable):
     unit = USD
     definition_period = YEAR
     reference = (
-        "https://www.ksrevenue.gov/pdf/ip21.pdf",
-        "https://www.ksrevenue.gov/pdf/ip22.pdf",
+        "https://www.ksrevisor.gov/statutes/chapters/ch79/079_032_0120.html",
+        "https://www.ksrevenue.gov/pdf/ip17.pdf#page=14",
+        "https://www.ksrevenue.gov/pdf/ip25.pdf#page=14",
     )
     defined_for = StateCode.KS
 
     def formula(tax_unit, period, parameters):
-        # 2021 Form K-40 instructions say this:
-        #   LINE 4 (Standard deduction or itemized deductions):
-        #   If you did not itemize your deductions on your federal return,
-        #   you may choose to itemize your deductions or claim the
-        #   standard deduction on your Kansas return whichever is to your
-        #   advantage.  If you itemized on your federal return, you may
-        #   either itemize or take the standard deduction on your Kansas
-        #   return, whichever is to your advantage.
-        # compute itemized deduction maximum
-        itm_deds_less_salt = tax_unit("itemized_deductions_less_salt", period)
-        uncapped_property_taxes = add(tax_unit, period, ["real_estate_taxes"])
-        return itm_deds_less_salt + uncapped_property_taxes
+        # K.S.A. 79-32,120(a) limits the Kansas itemized deduction to four
+        # federal categories, each at a year-specific share. Other federal
+        # itemized deductions (investment interest, casualty and theft losses,
+        # miscellaneous deductions) do not count. Property taxes are not limited
+        # by the federal cap on state and local taxes.
+        p = parameters(period).gov.states.ks.tax.income.deductions.itemized.rate
+        charitable = tax_unit("charitable_deduction", period)
+        medical = tax_unit("medical_expense_deduction", period)
+        qualified_residence_interest = tax_unit(
+            "deductible_mortgage_interest_tax_unit", period
+        )
+        property_taxes = add(tax_unit, period, ["real_estate_taxes"])
+        return (
+            p.charitable_contributions * charitable
+            + p.medical_expenses * medical
+            + p.qualified_residence_interest * qualified_residence_interest
+            + p.property_taxes * property_taxes
+        )
diff --git a/policyengine_us/variables/gov/states/ks/tax/income/ks_taxable_income.py b/policyengine_us/variables/gov/states/ks/tax/income/ks_taxable_income.py
@@ -10,12 +10,19 @@ class ks_taxable_income(Variable):
     reference = (
         "https://www.ksrevenue.gov/pdf/ip21.pdf",
         "https://www.ksrevenue.gov/pdf/ip22.pdf",
+        "https://www.ksrevisor.gov/statutes/chapters/ch79/079_032_0120.html",
     )
     defined_for = StateCode.KS
 
     def formula(tax_unit, period, parameters):
+        p = parameters(period).gov.states.ks.tax.income.deductions.itemized
         std_ded = tax_unit("ks_standard_deduction", period)
         itm_ded = tax_unit("ks_itemized_deductions", period)
-        deductions = where(itm_ded > std_ded, itm_ded, std_ded)
+        # K.S.A. 79-32,120(a)(1): before 2021, only federal itemizers may
+        # itemize on the Kansas return.
+        may_itemize = True
+        if p.federal_itemization_required:
+            may_itemize = tax_unit("tax_unit_itemizes", period)
+        deductions = where(may_itemize & (itm_ded > std_ded), itm_ded, std_ded)
         exemptions = tax_unit("ks_exemptions", period)
         return max_(0, tax_unit("ks_agi", period) - deductions - exemptions)
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		Limit Kansas itemized deductions to charitable contributions, medical care, qualified residence interest and property taxes at the K.S.A. 79-32,120(a) shares for each year, and require federal itemizing before 2021.