How Missouri income tax works: federal AGI, the federal tax deduction, 4.7%

Missouri has a graduated income tax on paper and a flat one in practice. There are eight brackets, but the top rate of 4.7% begins at $9,436 of Missouri taxable income for 2026, and the first $1,348 is taxed at nothing. For nearly everyone the arithmetic comes out to 4.7% of what is left after the standard deduction, less about $180. The return, Form MO-1040, starts from federal adjusted gross income, takes out a short list of Missouri subtractions, the largest of which since 2025 is every dollar of capital gain, allows a deduction for part of the federal income tax you paid, and then applies the federal standard deduction, $16,100 single and $32,200 married filing combined for 2026. Kansas City and St. Louis add a 1% earnings tax of their own on a separate return; nothing else in the state taxes income.

Because the starting line is federal AGI, everything the federal return does below that line is invisible here: the federal standard deduction, itemized deductions, the qualified business income deduction, the new deductions for tips, overtime, car-loan interest and seniors. The Department of Revenue has said so in writing about the four new ones. Everything above the line, an IRA contribution, a health savings account deposit, student loan interest, flows through and cuts Missouri tax too. A tipped worker who owes no federal tax on $8,000 of tips still owes Missouri $376 on them.

Who files

A full-year resident reports all income wherever earned and credits tax paid to another state on Form MO-CR. A nonresident with more than $600 of Missouri-source income files MO-1040 with Form MO-NRI, which figures the Missouri share; a resident files above $1,200. A part-year resident uses MO-NRI or MO-CR, whichever gives the lower tax. Married couples who filed jointly file a combined Missouri return, but it splits income between the spouses and taxes each share separately down the same chart, which is why the brackets are the same for every status. The moving-year rules are in Moving to Missouri.

Where it starts: federal AGI

Line 1 of the MO-1040 is federal adjusted gross income from Form 1040, line 11. The additions and subtractions are on Form MO-A, Part 1, and most households have one or two at most.

The additions. Interest on other states’ municipal bonds, a nonqualified withdrawal from a 529 or ABLE account that earned a Missouri deduction going in, and, for nonresidents, property tax deducted for a state that gives Missouri residents no matching break. That is nearly the whole list.

The subtractions. This is where the Missouri return gives money back.

The pension and Social Security exemptions are not on this list; they come off later, on MO-1040 line 8, from MO-A Part 3. See Missouri for retirees.

Capital gains, line 18. Since tax year 2025 Missouri subtracts the whole net capital gain from the federal return, short-term and long-term alike: stocks, real estate, crypto, the sale of a business. The gain goes on MO-A line 18 for the spouse who had it. A net capital loss gives no subtraction, because the loss already reduced federal AGI. Gains that come through a partnership or S corporation that elected Missouri’s pass-through entity tax do not qualify, and trusts and estates get nothing. Qualified dividends are not capital gains and are taxed at 4.7% like interest. One answer on the Department’s FAQ page says the subtraction begins with the 2026 return; the What’s New page and the 2025 Form MO-A say 2025 (verify).

529 contributions, line 12. Deposits to MOST or to any other state’s 529 plan are subtracted up to $8,000 per taxpayer and $16,000 on a combined return. The federal return never asks about them, so this is the subtraction most often forgotten.

The pension and Social Security exemption, line 8

Social Security is exempt for anyone 62 or older by December 31, with no income limit. Public pensions are exempt up to $48,967 for 2026, reduced by the Social Security exemption claimed. Private pensions, IRAs and 401(k)s get a $6,000 exemption per spouse that disappears a few thousand dollars above $25,000 single or $32,000 married of Missouri AGI. The mechanism is in the retirees article; the 62-or-older box on page 1 has to be checked or the Social Security exemption is denied.

The federal income tax deduction, lines 9 to 13

Missouri lets you deduct part of the federal income tax you owed for the year. Line 9 is your federal income tax liability after credits; line 12 is a percentage set by Missouri AGI; line 13 is the product, capped at $5,000, or $10,000 on a combined return.

The cap is $5,000 for every status except married filing combined, which gets $10,000. The brackets and the cap are not indexed.

It is worth less than it looks. A couple with $90,000 of Missouri AGI and $6,000 of federal tax deducts $900 and saves $42. It has one odd consequence: a federal credit that cuts your federal tax, the child tax credit for instance, raises your Missouri tax a little, because there is less federal tax to deduct.

The standard deduction, line 14

Missouri uses the federal standard deduction figures: $16,100 for single and married filing separately, $32,200 for married filing combined and qualifying widow(er), $24,150 for head of household, for 2026. The additional amount for age 65 or blindness follows the federal figure; the 2025 amounts were $2,000 single or head of household and $1,600 per married spouse, with 2026 to come. A head of household or qualifying widow(er) also gets a $1,400 additional exemption, shown on the 2026 Form MO-1040ES and on MO-1040 line 15. That is the only exemption; there are none for the taxpayer, spouse or dependents.

Itemizing is allowed only if you itemized federally. The Missouri itemized deduction is the federal Schedule A total, plus the Social Security, Medicare and self-employment tax you paid, minus state and local income taxes, on MO-A Part 2. Earnings tax paid to Kansas City or St. Louis stays in. Property tax and sales tax are not backed out, so the federal $40,000 state-and-local cap flows through to Missouri for those two.

The rate

Missouri taxable income runs through eight brackets that all fit inside the first $9,436.

From the 2026 Form MO-1040ES. The brackets are indexed each year; for 2025 the top rate began at $9,191. The shortcut: 4.7% of taxable income, minus $180.

On a combined return each spouse’s share runs the chart separately, so a couple gets two trips through the low rates, worth about $180 each. The rate has been 4.7% since 2025; the statute’s revenue triggers for further 0.1-point cuts were not met on the year ended June 30, 2026, so no cut is expected for 2027 (verify).

The credits

There is no state child tax credit, no child care credit and no general renter credit. The Working Family Tax Credit only reduces tax: a family whose Missouri tax is $300 and whose credit is $800 loses $500. The family and property-tax credits are covered in Credits and breaks for Missouri families and Missouri for retirees.

The earnings taxes in Kansas City and St. Louis

Kansas City and the City of St. Louis each levy a 1% earnings tax. A resident of either city pays it on all earnings wherever earned, including self-employment income; a nonresident pays it on wages for work physically performed inside the city. Employers withhold it and report it in box 19 of the W-2; the city returns are Form RD-109 in Kansas City and Form E-1 in St. Louis. A nonresident who worked some days outside the city claims a refund for those days, on Form RD-109NR in Kansas City by the federal filing deadline and Form E-1R in St. Louis. Both taxes were renewed by voters on April 7, 2026 for five more years. No county or school district in Missouri taxes income. The earnings tax is not a credit against the state tax, but it stays in the Missouri itemized deduction for those who itemize.

Withholding and estimated payments

Missouri withholding on wages is set by Form MO W-4, the state’s own certificate. Anyone who expects to owe $100 or more after withholding and credits must make estimated payments on Form MO-1040ES or through MyTax Missouri, due April 15, June 15, September 15 and January 15. The safe harbor is 100% of last year’s tax or 90% of this year’s (66 2/3% for farmers); there is no 110% rule for higher incomes. The people caught are the self-employed, landlords and retirees drawing on IRAs with no state withholding. The addition to tax is figured on Form MO-2210.

How to file

Most returns go in electronically with the federal return; the Department lists approved Free File Alliance software, and MyTax Missouri takes payments. The 2026 return is due April 15, 2027. With a federal extension and no Missouri balance due, check the box on the MO-1040 and attach Form 4868; the extension to October 15 is automatic. If you expect to owe, send Form MO-60 with the payment by April 15, because the extension does not extend the time to pay and a 5% addition plus interest applies after that date. Dates, forms and refund tracking are in Missouri calendar and forms.