How Montana Income Tax Works
Montana uses a progressive income tax with 2 brackets for 2026. State rates start at 4.7% on the lowest taxable earnings and rise to 5.65% on income above $47,500 for single filers — layered on top of the federal 10%–37% brackets.
Montana has no general sales tax — almost unique outside the no-income-tax states. The 2026 top rate also dropped from 5.9% to 5.65%.
Montana Job Market & Income Context
Agriculture and ranching, mining, and tourism (Glacier and Yellowstone gateway towns); rapid growth from out-of-state movers.
How Montana Income Tax Compares to Neighboring States
Total income tax (federal + state) on a $100,000 annual salary in 2026, single filer using the standard deduction:
| State | State Tax | Total Income Tax | vs. Montana |
|---|---|---|---|
| Montana (here) | $4,351 | $17,521 | — |
| Idaho | $4,505 | $17,675 | +$154 |
| Wyoming | $0 | $13,170 | -$4,351 |
| South Dakota | $0 | $13,170 | -$4,351 |
| North Dakota | $712 | $13,882 | -$3,639 |
A negative "vs." figure means that state collects less total income tax than Montana. Federal portion is identical across states; only state tax varies.
Frequently Asked Questions
What is the Montana state income tax rate for 2026?
Montana state income tax for 2026 ranges from 4.7% on the lowest bracket to 5.65% on income above $47,500 (single filer). Most middle-income earners hit the middle brackets; the top rate applies only to high earners.
How much income tax will I pay in Montana on a $100,000 salary?
For a single filer earning $100,000 in Montana in 2026, expect approximately $13,170 in federal income tax and $4,351 in Montana state income tax — for a total income tax of about $17,521, an effective rate of 17.5%. This excludes FICA (Social Security and Medicare), which adds roughly 7.65% on top.
What's the difference between effective and marginal tax rate?
Your marginal rate is the rate applied to your last dollar of taxable income — the bracket your top dollar lands in. Your effective rate is your total income tax divided by your total income — the average rate across everything you earned. Effective is always lower than marginal because lower brackets cover the first portions of your income at lower rates.
Does Montana tax retirement income, Social Security, or capital gains?
Federal rules: long-term capital gains use preferential rates (0%, 15%, 20%) — see our Capital Gains Tax Calculator. Social Security is taxable federally if your combined income exceeds certain thresholds. Montana's treatment of retirement income, Social Security, and capital gains varies — many states fully or partially exempt Social Security, and some provide pension exclusions. Consult Montana's Department of Revenue for specifics.
How is this Montana income tax estimate calculated?
We apply the 2026 federal IRS tax tables (10%–37% across seven brackets) and Montana's 2026 state tax schedule to your taxable income (gross income minus the standard deduction). The calculator handles wages, self-employment income (with SE tax and the deductible half), and other income; you can also switch to itemized deductions. Tax credits, AMT, and preferential capital gains rates are not modeled — this is an estimate of ordinary income tax only.