Montana charges 4.7-5.65% state income tax. Use the side income tax calculator pre-loaded with Montana rates.
Open Side Income Tax Calculator →Side income in Montana is subject to federal income tax at your marginal rate, self-employment tax if applicable, and up to 5.65% Montana state income tax. Because side income typically stacks on top of your W-2 salary, it is often taxed at your highest marginal rates. The combined marginal rate on side income can easily exceed 40% for mid-to-high earners. This calculator breaks down exactly what you keep from each dollar of side income in Montana.
Montana uses a graduated income tax with brackets ranging from 4.7-5.65%. Lower income is taxed at lower rates, with the 5.65% top rate applying only to income in the highest bracket. This progressive structure means your effective state tax rate is always lower than the top marginal rate. Montana does not have local income taxes, so the state graduated rate is the total state-level income tax burden.
The table below shows what you actually keep at five salary levels in Montana, accounting for federal tax, FICA, and Montana's graduated (4.7-5.65%) state tax.
See how Montana compares to other West states. Each link takes you to the side income tax calculator landing page for that state.
For a comprehensive breakdown of Montana’s tax structure, salary comparisons, cost-of-living analysis, and more, visit the full Montana take-home pay page.