MO-1040A: Single/Married with One Income Tax Return - Fillable and Calculating Form (2025)
Missouri · Missouri DOR · Used for tax years 2025
Form MO-1040A is Missouri’s 2025 Individual Income Tax Return for Single/Married (One Income) filers. It reports income, deductions, Missouri tax, withholding, and estimated tax payments to calculate a refund or amount due.
What you'll need
- Your federal return: Use it for federal adjusted gross income and federal tax amounts.
- Forms W-2 and 1099: Attach copies to support Missouri tax withheld on Line 11.
- Estimated payment information: Line 12 asks for Missouri estimated tax payments made for 2025, including any 2024 overpayment applied to 2025.
- If you itemize deductions: Attach pages 1 and 2 of Federal Form 1040 or 1040-SR and Federal Schedule A. If you are subject to additional Medicare tax, also attach Federal Form 8959.
- If you have an approved federal extension: Attach a copy of Form 4868 and select the federal extension box.
- If you direct part of your refund to a Missouri MOST 529 Education Plan: Include Form 5632. You will need the 11-digit account number for each account receiving a contribution.
How to file
Complete the return using black ink only, and do not staple it. Sign the return. If filing combined, both spouses must sign. The form accepts signing or entering your name in the signature field.
Mail a return with a balance due to:
Missouri Department of Revenue
P.O. Box 3370
Jefferson City, MO 65105-3370
Mail a return with a refund or no amount due to:
Missouri Department of Revenue
P.O. Box 3222
Jefferson City, MO 65105-0500
The form also lists incometaxprocessing@dor.mo.gov for submission of individual income tax returns and fax (573) 522-1762. For inquiries and correspondence, it lists income@dor.mo.gov.
Common mistakes
- Using the wrong ink or stapling the return: The form says to use black ink only and not to staple.
- Entering federal withholding on Line 4a: Enter tax from your federal return, not federal income tax withheld.
- Missing a spouse’s signature: Both spouses must sign a combined return.
- Completing the itemized deduction section without federal itemized deductions: Complete this section only if you itemized on your federal return. Attach the required federal return pages and Schedule A.
- Missing the extension attachment: If you select the approved federal extension box, attach a copy of Form 4868.
- Failing to round the calculated tax: The tax chart directs you to round to the nearest whole dollar before entering the tax on Line 10.
Questions people ask
What standard deduction amounts are listed for 2025?
The form lists $15,750 for Single or Married Filing Separate, $23,625 for Head of Household, and $31,500 for Married Filing Combined or Qualifying Widow(er). If you are age 65 or older, blind, or claimed as a dependent, the form directs you to your federal return or page 6 of the instructions.
Can I apply an overpayment to next year’s estimated tax?
Yes. Enter on Line 15 the amount of your overpayment from Line 14 that you want applied to your 2026 estimated tax.
Can I donate part of my overpayment to a trust fund?
Yes. The form allows contributions to any one or all of the listed trust funds on Line 16. Enter the donation amounts in the fund boxes and add them for the total donation.
Can I put my refund into a Missouri MOST 529 Education Plan?
Yes. Include Form 5632 with your return. You must have an open Missouri MOST 529 Education Plan account administered by the Missouri Education Program, and the total deposit must be at least $25. You may contribute to up to four accounts. Enter the total from Form 5632, Line E, on MO-1040A, Line 17. If the requested deposit exceeds your available refund after an adjustment, the Department will cancel the deposit and issue a refund to you. If your refund is used to pay another debt, the Department will cancel the deposit.