Form MO-A at a glance
What it is: Form MO-A 2025 is the Individual Income Tax Adjustments form.
A filled-in Form MO-A example: a single filer with exempt federal interest
How to fill out Form MO-A, box by box
Name
Under Name, enter your Social Security Number, First Name, M.I., Last Name and Suffix.
Enter the Spouse's Social Security Number and the Spouse's First Name, M.I., Last Name and Suffix.
Additions
Line 1: Interest on state and local obligations other than Missouri source.
Line 3: Nonqualified distribution received from a qualified 529 plan not used for qualified expenses.
Line 4: Food Pantry contributions included on Federal Schedule A.
Line 5: Nonresident Property Tax.
Line 6: Nonqualified distribution received from a qualified Achieving a Better Life Experience Program (ABLE) not used for qualified expenses. Line 7, Total Additions: Add Lines 1 through 6. Enter here and on Form MO-1040, Line 2.
Subtractions
Subtractions. Line 8: Interest from exempt federal obligations included in federal adjusted gross income. Attach a detailed list or all Federal Form(s) 1099.
Line 9: Any state income tax refund included in federal adjusted gross income.
Line 10: Military Retirement Benefits (see instructions on page 14).
Line 12: Exempt contributions made to a qualified 529 plan.
Line 13: Qualified Health Insurance Premiums. Attach the Qualified Health Insurance Premiums Worksheet (Form 5695) and supporting documentation.
Part 1 Continued
Part 1 Continued. Line 14: Missouri depreciation adjustment (Section 143.121, RSMo.). Sold or disposed property previously taken as addition modification.
Line 15: Exempt contributions made to a qualified Achieving a Better Life Experience Program (ABLE).
Line 16: Agriculture Disaster Relief.
Line 17: Business Income Deduction. See worksheet on page 16 of MO-1040 Instructions.
Line 18: Capital Gain.
Line 19, Total Subtractions: Add Lines 8 through 18. Enter here and on Form MO-1040, Line 4.
Part 2 - Missouri Itemized Deductions
Complete this section only if you itemize deductions on your federal return.
Attach your Federal Form 1040 (pages 1 and 2) and Federal Schedule A.
Line 1: Total federal itemized deductions from Federal Form 1040 or Federal Form 1040-SR, Line 12e.
Lines 2, 3, 4 and 5: 2025 Social security tax (Yourself), 2025 Social security tax (Spouse), 2025 Railroad retirement tax - Tier I and Tier II (Yourself) and 2025 Railroad retirement tax - Tier I and Tier II (Spouse).
Line 6: 2025 Medicare tax - Yourself and Spouse (see page 16 of MO-1040 Instructions). Line 7: 2025 Self-employment tax (see page 16 of MO-1040 Instructions).
Line 8: Total. Add Lines 1 through 7.
Line 11: Net state income taxes. Subtract Line 10 from Line 9 or enter Line 7 from worksheet below.
Line 12: Missouri Itemized Deductions. Subtract Line 11 from Line 8. Enter here and on Form MO-1040, Line 14.
Complete this worksheet only if your total state and local taxes included in your federal itemized deductions exceeded $40,000 ($20,000 if married filing separately) or you were required to complete a federal worksheet to calculate Federal Schedule A, Line 5e. (checked November 11, 2026)
Part 2 Worksheet - Net State Income Taxes, Line 11. Line 1: Enter the sum of your state and local taxes on Federal Form 1040 or Federal Form 1040-SR, Schedule A, Line 5d. Line 2: State and local income taxes from Federal Form 1040 or Federal Form 1040-SR, Schedule A, Line 5a. Line 3: Earnings taxes included on Federal Form 1040 or Federal Form 1040-SR, Schedule A, Line 5a. Line 4: Subtract Line 3 from Line 2. Line 5: Divide Line 4 by Line 1. Line 6: Enter the amount from Federal Schedule A, Line 5e. Line 7: Multiply Line 6 by percentage on Line 5. Enter here and on net state income taxes, Line 11, above.
Part 3 - Pension and Social Security/Social Security Disability
Public Pension Calculation: Pensions received from any federal, state, or local government.
Line 1: Taxable pension for each spouse from public sources from Federal Form 1040 or Federal Form 1040-SR, Line 5b.
Line 2: Amount from Line 1 or $47,633 (maximum social security benefit), whichever is less. (checked November 11, 2026)
Line 4: Subtract Line 3 from Line 2. If Line 3 is greater than Line 2, enter $0. (checked November 11, 2026)
Line 5: Total public pension. Add amounts on Lines 4Y and 4S.
Private Pension Calculation: Annuities, pensions, IRAs, and 401(k) plans funded by a private source.
Line 4: Select the appropriate filing status and enter the amount on Line 4. Married Filing Combined (joint federal) - $32,000; Single, Head of Household, and Qualifying Widow(er) - $25,000; Married Filing Separate - $16,000. (checked November 11, 2026)
Line 7: Amounts from Line 6Y and 6S or $6,000, whichever is less. (checked November 11, 2026)
Line 9: Total private pension, subtract Line 5 from Line 8. If Line 5 is greater than Line 8, enter $0. (checked November 11, 2026)
Social Security or Social Security Disability Calculation: To be eligible for social security deduction you must be 62 years of age by December 31 and have selected the 62 and older box on page 1 of Form MO-1040. Age limit does not apply to social security disability deduction.
Line 4: Total social security/social security disability. Add Lines 3Y and 3S.
Add Line 5 (Section A), Line 9 (Section B), and Line 4 (Section C) from Form MO-A. Enter total amount here and on Form MO-1040, Line 8.
More rules for Form MO-A
Attach to Form MO-1040. Attach your federal return. See information beginning on page 12 to assist you in completing this form.
Sources
[1] Form MO-A 2025, Individual Income Tax Adjustments, Missouri Department of Revenue (the Official source link on this page).