You must file an amended return if:
- You learn there is an error on your original return
- You make changes to your federal income tax return
- The IRS makes changes to your federal income tax return
Your amended Montana income tax return is due 90 days after receiving a notification of the change from the IRS or after filing your amended federal income tax return.
You may choose to file an amended return for:
- 2015 or later
- Three years after the original due date.
- 2014 or before
- Five years after the original due date.
Changing or Correcting Your Return
When you file an amended return, you will need to use the same form as your original return. You can find previous year’s forms in My Revenue:
- Montana Individual Income Tax Return Long Form (Form 2)
- Montana Individual Income Tax Return Short Form (Form 2EZ)
Mark the box labeled “Mark this box if this is an amended return” at the top of the form.
Include copies of all of schedules you submitted with your original return, even if none of the amounts have changed as well as all new schedules you are submitting for the first time.
If you need to file multiple returns, please file each amended return separately from other returns.
Please mark the “NOL” box in the upper-left corner of your Form 2 if you are amending your tax return to carry back a net operating loss.
If your amended return results in a refund, we’ll mail a check to the address included on the return. If you overpaid your tax, we’ll apply interest to your refund at the same rate we charge on past-due taxes.
Learn more about Late Fees, Interest, and Penalties.
Amended Returns and Penalties
If you owe additional taxes after you amend your return, you should pay the tax, along with the annual interest, with your amended return. If you pay the tax owed and interest, we’ll assume an amended return is requesting a waiver of the late payment penalty.
We figure any late pay penalty and interest on unpaid tax from the original return’s due date.
Other Important Information
- If you itemized deductions, you should recalculate to see if your income changes affect the limits on medical expenses and miscellaneous itemized deductions.
- A change to your income can also change your taxable social security benefits, partial pension and annuity income exemption, or standard deduction.
- If you are amending from filing jointly to filing separately (on the same or separate forms), include a detailed breakdown showing the income and deductions for each spouse.