You must file a Montana Individual Income Tax return if:
- You were a resident or part-year resident of Montana, or
- You were a nonresident who received Montana source income, and
- Your federal gross income, excluding unemployment compensation, meets the Montana filing threshold.
You should file a return if you had Montana tax withheld from your paycheck or if you paid estimated income tax, even if you aren't required to file a return.
Filing a return is the only way to get your refund.
Montana Filing Thresholds
| Filing Status | Under 65 | 65 and Older |
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| Single or Married Filing Separately | $5,540 | $8,500 |
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| Head of Household | $11,180 | $14,040 |
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| Married Filing Jointly | $11,180 | Single spouse over 65: $14,040
Both spouses over 65: $17,000 |
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Beginning with Tax Year 2024, taxpayers must file a Montana tax return if they have a federal filing requirement, considering any Montana additions.
Calculating Your Montana Taxes
The Montana Individual Income Tax Instruction Booklet has the full instructions for calculating your tax liability, but you can get a rough estimate by following these steps:
- Calculate your Federal Adjusted Gross Income (FAGI)
- Add your Montana additions using the Montana Additions Schedule (Form 2, Page 3) (15-30-2110, MCA (repealed as of 12/31/2023)
- Subtract your Montana subtractions using the Montana Subtractions Schedule (Form 2, Page 4) (15-30-2110, MCA (repealed as of 12/31/2023))
- Subtract your deductions, using either your standard deduction (repealed as of 12/31/2023) or the Itemized Deduction Schedule (Form 2, Page 6)
- Subtract your total exemptions (repealed as of 12/21/2023)
- You now have your Montana taxable income
- Use your Montana taxable income on the Montana Tax Rates Table
- Apply your tax rate to your Montana taxable income
- Subtract any tax credits you qualify for in this order:
- 2% capital gains tax credit
- Nonrefundable, single-year tax credits you can't carryover
- Nonrefundable tax credits you can carryover
- Refundable tax credits
Nonrefundable tax credits are reported on the Nonrefundable Credits Schedule (Form 2, Page 9). Refundable tax credits are reported on the Other Payments and Refundable Credits Schedule (Form 2, Page 11), with the exception of the Montana Earned Income Credit which is reported on Form 2, Page 1, line 23b. Most tax credits must be calculated on their own form. A full listing of tax credits and their forms are included in the Montana Individual Income Tax Instruction Booklet.
Beginning with Tax Year 2024, under Senate Bill 399 (2021), the calculation of Montana tax will change. More information about this change is here. Here are the updated steps to determine your Montana income tax.
- Calculate your federal taxable income.
- Add your Montana additions (15-30-2120,MCA)
- Subtract your Montana subtractions (15-30-2120,MCA)
- You now have your Montana taxable income
- Use your Montana taxable income on the Montana Tax Rates Table
- Apply your tax rate to your Montana taxable income based on the character of the income (ordinary income or long-term capital gains)
- Subtract any tax credits you qualify for in this order:
- Nonrefundable, single-year tax credits you can't carryover
- Nonrefundable tax credits you can carryover
- Refundable tax credits