Montana Income Tax Calculator
Montana income tax is calculated on your taxable income after deductions and exemptions. This calculator estimates your Montana state income tax liability for the current tax year. Enter your annual gross income, choose your filing status (single, married filing jointly, married filing separately, or head of household), and add any pre-tax deductions to see your estimated state tax, effective tax rate, and marginal bracket. Results update in real time as you adjust your inputs. The calculator covers Montana state income tax only; federal income tax, FICA payroll taxes, and any local income taxes your city or county imposes are separate. All rates and brackets are sourced directly from Montana Department of Revenue and are verified for the current tax year. Use this tool alongside the federal income tax calculator to see your combined total tax liability. Effective rate and marginal rate are both shown so you can evaluate the impact of additional income, filing status changes, or increased pre-tax contributions to a 401(k) or similar plan.
Montana applies a flat income tax rate of 4.9% to all taxable income. On a $60,000 salary (single filer) the state income tax is $2,665.60, an effective rate of 4.44%.
How Montana income tax works
Montana converted from a graduated income tax to a flat rate of 4.9% effective January 1, 2024, under Montana SB 399 (2023), codified at MCA §15-30-2103. Prior to 2024, Montana had a graduated rate structure with a top rate of 6.75%. The flat rate applies to all Montana taxable income regardless of filing status or income level. Your result updates the page link, so you can copy a permalink to any calculation.
taxable income = gross income - standard deduction
state income tax = taxable income x flat rate / 100
effective rate = state income tax / gross income x 100
Montana income tax: frequently asked questions
How much is the Montana income tax on a $60,000 salary?
A single filer earning $60,000 a year in Montana has a taxable income of $54,400.00 after the standard deduction. The computed state income tax is $2,665.60, an effective rate of 4.44%. Enter your own income above for an exact figure.
What is the Montana state income tax rate?
Montana applies a flat income tax rate of 4.9% to all taxable income, regardless of income level or filing status.
What filing statuses does Montana income tax apply to?
Montana income tax applies to single filers, married couples filing jointly, head of household filers and married couples filing separately. Bracket thresholds and standard deductions may differ by filing status.
What is Montana's state income tax rate for 2025?
Montana's flat income tax rate is 4.9% for tax year 2025. This rate was established by Montana SB 399 (2023) and took effect January 1, 2024, replacing a graduated rate structure that previously topped out at 6.75%. The rate is codified at MCA §15-30-2103.
How does Montana's standard deduction work?
Montana allows a standard deduction equal to 20% of your gross income, up to an annually adjusted maximum. For 2024, the approximate maximums are $5,600 for single and married filing separately filers, and $11,200 for married filing jointly and head of household filers. Because these maximums are inflation-adjusted each year, confirm the current amounts with the Montana Department of Revenue at mtrevenue.gov.
When did Montana switch to a flat income tax?
Montana adopted a flat income tax rate of 4.9% effective January 1, 2024, under SB 399 passed by the 2023 Montana Legislature. Before that change, Montana used a graduated rate structure with multiple brackets and a top marginal rate of 6.75%.
Does Montana allow federal tax deductions on state returns?
Montana previously allowed a deduction for federal income taxes paid, which was a notable feature of the Montana return. As part of the 2023 tax reform (SB 399), this deduction was eliminated effective January 1, 2024, coinciding with the shift to the flat rate. Check the Montana Department of Revenue for current deduction rules.
Official sources
- Montana income tax rates (tax year 2025): Montana Department of Revenue, as at Jun 12, 2026.
Reviewed by the CalculatorHub team, edited by James Graham, 11 June 2026. See our methodology. General information, not financial or tax advice.