Missouri does not tax Social Security benefits at the state level. For tax years beginning on or after January 1, 2024, if you are 62 or older by the end of the year, or you receive Social Security disability payments at any age, 100% of the Social Security income on your federal return can be subtracted on your Missouri return. There is no income cap. Federal taxes on Social Security in Missouri are a separate matter, and depending on your other income, up to 85% of your benefits may still be taxable on your federal return.
1Missouri Department of Revenue. Pension 2024Who Qualifies for Missouri’s Exemption
Missouri Revised Statutes Section 143.125 defines the “benefits” eligible for the deduction as Social Security received by someone age 62 or older, or Social Security disability benefits. Two paths, two different rules.
2Missouri Revisor of Statutes. Missouri Revised Statutes Section 143.125If you are 62 or older by December 31 of the tax year, you qualify based on age alone. Your other income does not matter. Before 2024, Missouri capped the deduction for filers whose Missouri adjusted gross income exceeded $85,000 single or $100,000 joint. Those caps are gone.
1Missouri Department of Revenue. Pension 2024If you receive Social Security Disability Insurance (SSDI), the exemption applies regardless of your age. There is no age box to check for disability benefits.
3Missouri Department of Revenue. Pension FAQsOne boundary worth noting: if you are younger than 62 and collecting Social Security for a reason other than disability, such as early survivor benefits, you do not qualify for the Missouri deduction. Those benefits remain in your Missouri taxable income until you reach 62.
2Missouri Revisor of Statutes. Missouri Revised Statutes Section 143.125How to Claim the Deduction on Your Missouri Return
Every January the Social Security Administration mails Form SSA-1099, which shows your total benefits in Box 3 and any voluntary federal withholding in Box 6. If yours does not arrive by late January, you can download a replacement through your my Social Security account.
4Social Security Administration. POMS GN 05002.220 – Replacement Social Security Benefit StatementThe deduction itself is calculated on Form MO-A (Individual Income Tax Adjustments), Part 3, Section C. On Form MO-1040, check the “62 and older” box on page 1 if you qualify by age. The resulting subtraction flows to Line 8 of the MO-1040. For SSDI recipients, no age box is required.
5Missouri Department of Revenue. Form MO-A – 2025 Individual Income Tax AdjustmentsTax software handles the MO-A calculation automatically once you enter the SSA-1099 and confirm your age. Still, it is worth looking at Line 8 before you file to make sure the full amount actually appears there. State-specific changes occasionally lag in software updates.
Federal Tax Is a Different Story
Missouri’s exemption covers only your state return. The IRS taxes Social Security based on “provisional income,” which is your adjusted gross income plus any tax-exempt interest plus half of your Social Security benefits. Congress set the thresholds in 1993 and never indexed them for inflation, so more retirees cross them each year.
- Single filers with provisional income between $25,000 and $34,000: up to 50% of benefits are taxable.
- Single filers above $34,000: up to 85% of benefits are taxable.
- Married filing jointly between $32,000 and $44,000: up to 50% of benefits are taxable.
- Married filing jointly above $44,000: up to 85% of benefits are taxable.
One trap: if you are married, file separately, and live with your spouse at any point during the year, your base amount is zero. Up to 85% of your benefits can be federally taxable from the very first dollar of provisional income. This filing status is almost always the worst option for Social Security recipients.
6Office of the Law Revision Counsel. 26 USC 86 – Social Security and Tier 1 Railroad Retirement BenefitsWages, pensions, investment earnings, rental income, and even tax-exempt municipal bond interest all feed the provisional income calculation. On the Missouri side none of that matters for Social Security. On the federal side, it is the whole game.
Withholding and Estimated Payments
Social Security does not automatically withhold federal income tax. If you expect to owe, file Form W-4V (Voluntary Withholding Request) with the SSA to have a flat percentage pulled from each payment. Your only choices are 7%, 10%, 12%, or 22%. No other percentage and no custom dollar amount is permitted.
7Internal Revenue Service. Form W-4V (Rev. January 2026) Voluntary Withholding RequestIf none of those percentages fit, the alternative is quarterly estimated tax payments on Form 1040-ES. Deadlines fall on April 15, June 15, September 15, and January 15 of the following year. The IRS typically waives the underpayment penalty if you owe less than $1,000 at filing time.
Lump-Sum Back Payments
If a disability claim or other award produces a lump-sum payment covering prior years, the entire amount lands in Box 3 of the SSA-1099 for the year you actually received it. Calculated the default way, that lump can push a large portion of your benefits into the taxable column federally.
The IRS lump-sum election method lets you recompute the taxable share using the income you had in the earlier year the payment covers. If the recalculation is lower, check the box on Form 1040, line 6c, and use that figure. You do not file an amended return for the prior year. The worksheets in IRS Publication 915 walk through the comparison.
8Internal Revenue Service. Publication 915, Social Security and Equivalent Railroad Retirement BenefitsFor Missouri, the lump-sum size does not matter. As long as you meet the age or disability requirement, the entire amount is deductible on the state return. The lump-sum election is purely a federal tool.
What About Kansas City and St. Louis Earnings Taxes?
Both Kansas City and St. Louis levy a 1% earnings tax on income earned within city limits. Neither applies it to Social Security. Kansas City states that Social Security payments are not subject to its earnings tax.
9City of Kansas City. Tax FAQsSt. Louis exempts Social Security along with pensions, dividends, interest, and other retirement income.
10City of St. Louis. STL Companies Earnings/Payroll Tax ExemptionsNo level of Missouri taxation touches your Social Security check.
Medicare Premiums React to Your Income
IRMAA, the income-related monthly adjustment amount for Medicare, is not a tax but behaves like one. Medicare looks at your modified adjusted gross income from two years prior to decide whether you pay higher Part B and Part D premiums. For 2026, elevated premiums kick in above $109,000 single or $218,000 joint. At the top tier, individuals with income of $500,000 or more pay $689.90 per month for Part B, compared with the standard $202.90.
11Centers for Medicare & Medicaid Services. 2026 Medicare Parts A and B Premiums and DeductiblesThe MAGI figure used for IRMAA includes any federally taxable portion of your Social Security benefits. A large lump-sum payment or an unusually high pension distribution can spike your income and trigger a surcharge two years later. Those premiums come straight out of your Social Security check, cutting the net amount you receive each month.