How to Use This Calculator
Enter your income, filing status, and any deductions. The calculator computes your Montana state income tax alongside your federal tax, showing exactly how much goes to each and what you take home.
The most useful thing to try? See how Montana's flat 5.9% rate affects different income levels, then test how deductions and retirement contributions change your bottom line.
Here's what each field means:
Annual Income is your total earnings before any taxes. Include wages, freelance income, investment income, and any other sources.
Filing Status determines which deductions and exemptions apply. Montana uses filing statuses similar to the federal system.
Montana Income Tax: What You Need to Know
Montana uses a flat income tax of 5.9% on all taxable income. Unlike states with progressive brackets, everyone pays the same percentage regardless of how much they earn. A teacher making $45,000 and a CEO making $500,000 both pay 5.9%.
Montana transitioned from a seven-bracket progressive system (1% to 6.75%) to a flat 5.9% rate in 2024 as part of a major tax reform under Governor Gianforte. The state now conforms to the federal standard deduction, making filing simpler. Montana has no sales tax, which partially offsets the income tax burden. Montana does not tax Social Security benefits and offers a pension income exclusion.
A Real Example
Let's say you're a single filer earning $70,000 in Montana. After applying the standard deduction of $14,600, your approximate Montana state income tax would be around $3,254, for an effective state tax rate of about 4.6%.
That's just the state portion. Federal income tax and FICA taxes are additional.
Deductions and Exemptions
Standard Deduction: $14,600 for single filers and $29,200 for married couples filing jointly.
Federal standard deduction conformity, personal exemption. Montana does not tax Social Security and offers a partial pension exclusion. The state also provides various credits including a property tax credit for elderly homeowners.
Local Taxes
No local income taxes in Montana.
Recent Changes
The flat 5.9% rate took effect in 2024, replacing rates of 1% to 6.75%. Montana is also considering further rate reductions in upcoming legislative sessions.
How to Use This Calculator Strategically
Model a raise or job change. With a flat tax, the math is simpler — every additional dollar is taxed at 5.9%. But deductions and credits can still shift your effective rate.
Compare filing statuses. Even with a flat rate, different filing statuses unlock different deduction amounts that can affect your bottom line.
Plan retirement contributions. See how 401(k) or IRA contributions reduce your Montana taxable income and lower your state tax bill.
Evaluate a move. Compare Montana's flat 5.9% rate to other states. Depending on your income level, a flat tax state might save you money — or cost you more — compared to a progressive system.
References
- Montana Department of Revenue. (2025). Individual Income Tax.
This calculator is for educational purposes only and does not constitute tax or financial advice. Tax rates and rules change regularly. Consult a qualified tax professional for guidance specific to your situation.