Missouri Tax Deadlines

Individual Filing Deadline

Missouri individual income tax returns (Form MO-1040) are due April 15, 2026, matching the federal deadline. If you cannot file by this date, Missouri grants an automatic 6-month extension to October 15, 2026. However, you must pay at least 90% of your tax liability by the original April 15 deadline to avoid penalties and interest. File an extension request using Form MO-60.

Business Entity Deadlines

• Partnerships (Form MO-1065): Due March 16, 2026, with a 6-month extension to September 15, 2026. Missouri partnerships must file an informational return and issue K-1s to partners.
• S Corporations (Form MO-1120S): Due March 16, 2026, with extension to September 15, 2026. S-corps pass income through to shareholders but must still file a Missouri return.
• C Corporations (Form MO-1120): Due April 15, 2026, for calendar-year filers, with extension to October 15, 2026. Missouri corporate income tax is 4% of Missouri taxable income.
• Nonprofits: Due May 15, 2026, with extension to November 15, 2026. Tax-exempt organizations must file if they have Missouri unrelated business income.

Estimated Tax Payments in Missouri

Missouri requires quarterly estimated tax payments if you expect to owe $100 or more in state income tax after subtracting withholding and credits. Use Form MO-1040ES to submit payments. The quarterly due dates are April 15, June 15, and September 15 of 2026, and January 15, 2027. Underpayment penalties may apply if you fail to pay at least 90% of the current year's liability or 100% of the prior year's liability.

Missouri Tax Credits and Deductions

Missouri offers several tax credits that can reduce your overall liability and affect estimated payment calculations. These include the Property Tax Credit (Circuit Breaker) for eligible seniors and disabled individuals, the Missouri Earned Income Tax Credit (equal to 10% of the federal EITC), and credits for contributions to Missouri 529 education savings plans (MOST). Missouri also allows a deduction for 100% of federal income taxes paid, which is relatively unique among states.

Payment Methods

Missouri accepts tax payments through several channels: the Missouri Department of Revenue online portal at dor.mo.gov (free for bank account payments), credit or debit card payments through approved processors (convenience fees apply), and mail with paper vouchers and check or money order payable to the "Director of Revenue." Missouri also supports electronic funds transfer for business taxpayers.