M1X: Amended Minnesota Income Tax (2025)

Minnesota · Minnesota DOR · Used for tax years 2025

Form M1X is used to amend a 2025 Minnesota Individual Income Tax return. It reports changes to income, tax, credits, and payments and calculates any resulting refund or amount due.

Who files this form

Use the 2025 Form M1X to correct an original 2025 Minnesota Individual Income Tax return, Form M1. Use this version only for tax year 2025.

If the IRS changes or audits your federal return, or you amend your federal return, and the changes affect your Minnesota return, you must file an amended Minnesota return.

Do not file Form M1X only to change banking information. You also cannot use it to change from married filing jointly to married filing separately after the original return’s due date.

When it's due

  • Tax year 2025: April 15, 2026 is the original return’s due date for most taxpayers. You cannot change from married filing jointly to married filing separately after that due date.

What you'll need

Have your original 2025 Form M1, the Form M1X instructions, and the 2025 Individual Income Tax Instructions available. If your return was previously adjusted, use the corrected amounts from your earlier amendment, notice of change, or audit report.

Include these documents when applicable:

  • Any corrected schedules and related forms supporting your changes.
  • A complete copy of Form 1040X if you filed an amended federal return.
  • A complete copy of the IRS adjustment notice if you are amending because of an IRS adjustment.
  • An explanation of each change. Attach another sheet if needed.
  • If changing total subtractions, a list of corrected subtractions from Form M1 lines 5 through 7 and corrected Schedules M1M and M1MB.
  • A court appointment authorizing you to represent another taxpayer if you are filing for that person. For a refund claimed on behalf of a deceased taxpayer, also include Form M23.

How to file

  1. Enter your identifying information, original and corrected filing statuses, and the reason for amending.
  2. For lines 1 through 22, enter original or previously adjusted amounts in column A, changes in column B, and correct amounts in column C. Show decreases in parentheses and leave column B blank for unchanged lines.
  3. Complete the remaining lines, explain your changes, and include required attachments.
  4. Sign the return. Your spouse must also sign a joint return. A paid preparer must sign and include their preparer identification number.

Electronic filing: Beginning with tax year 2025, Form M1X may be filed electronically.

Mail filing: Send the completed form and required enclosures to:

Minnesota Amended Individual Income Tax

Mail Station 1060

St. Paul, MN 55146-1060

Payment: Pay electronically at www.revenue.state.mn.us or by check. To create a check payment voucher, select Make a Payment under Top Tasks for Individuals, then Check or Money Order on that website.

Common mistakes

  • Using the wrong year’s form: Use the 2025 Form M1X only to amend a 2025 Form M1.
  • Stapling attachments: Do not use staples on anything you submit.
  • Leaving out changes: Missing a required column B amount delays processing. A refund on line 27 or tax due on line 29 requires at least one increase or decrease in column B on lines 1 through 22.
  • Replacing a negative result with zero: If line 26 is negative, enter the negative amount, not zero.
  • Including spouse details on a separate return: Do not include your spouse’s name, birth date, or Social Security number when filing separately.
  • Treating M1X as your full unpaid balance: If you have unpaid taxes on your original Form M1, Form M1X will not show your corrected balance due.
  • Using estimated tax funds incorrectly: An M1X refund cannot be applied to your estimated tax account, and estimated tax funds cannot pay the amount on line 29.

Questions people ask

How soon must I report federal changes?

You have 180 days to file an amended Minnesota return if the federal changes affect your Minnesota return. If they do not, you have 180 days to send an explanation letter and a complete copy of Form 1040X or the IRS correction notice to Minnesota Department of Revenue, Mail Station 7703, 600 N. Robert St., St. Paul, MN 55146-7703.

Can I receive my refund by direct deposit?

Yes. Complete line 28 with your checking or savings account information. The routing number must have nine digits. The account number may contain up to 17 numbers and letters, with no hyphens, spaces, or symbols. If the information is incorrect or your financial institution does not accept it, the department will send a paper check.

Can an income change affect other credits or refunds?

Yes. It may affect refundable and nonrefundable credits, your property tax refund, and alternative minimum tax. Include copies of all schedules that change.

When do I pay additional tax?

The amount on line 29 is due when you file the amended return. Interest applies to unpaid tax plus penalty from the regular due date until paid in full. If tax and interest are not fully paid when you file, the department will assess a late payment penalty and additional interest on your first bill.

Where can I get help?

Visit www.revenue.state.mn.us or call 651-296-3781 or 1-800-652-9094 during business hours.

Official sources

All versions of M1X