Montana Income Tax Calculator 2026

How Montana taxes income

Montana runs 2 tax brackets, starting at 4.70% and reaching 5.65% on the highest incomes. The rates apply in slices: the first slice of your income is taxed at the lowest rate, the next slice at the next rate, and so on.

This is the part most people get wrong. Reaching the 5.65% bracket does not mean 5.65% of your income goes to Montana — only the portion above $47,500 is taxed at that rate. On $85,000, Montana actually takes $3,442, which is 4.05% of the whole salary.

Montana subtracts a standard deduction of $16,100 (single) or $32,200 (married filing jointly) before applying those brackets.

How Montana compares to the other 50

On $85,000, a single filer pays $3,442 in Montana state income tax. That ranks 35th out of 51 — toward the expensive end.

For scale: 9 states charge nothing at all, and at the other end Oregon takes $6,604 on the same salary.

Income tax is only one of the three big state taxes, though. A state with no income tax often has higher property tax, and a state with high income tax may have low property tax. Ranking states on this one number alone is the most common mistake in these comparisons.

What filing status changes in Montana

On the same $85,000 salary, the four filing statuses do not produce the same bill. Filing single costs $19,814 in total tax; filing jointly costs $14,874, $4,940 less.

Part of that difference is federal and part is Montana's own — its brackets and deduction differ by status. We have not yet confirmed Montana's joint brackets against the state's own schedule, so the joint figure here is conservative and the result says so.

Head of household sits between the two at $16,892, and married filing separately at $19,814. Filing separately is almost never cheaper, but it exists for situations where the tax is not the deciding factor.

What $85,000 looks like in each paycheck

Annual figures are how tax is calculated, but not how anyone experiences it. Spread across the year, $85,000 in Montana comes to $2,507 every two weeks after federal tax, FICA and Montana state tax — from a gross of $3,269.

Paid monthly, that is $5,432 landing in your account against $7,083 gross. Paid weekly, $1,254 out of $1,635.

Your actual paycheck will differ from these because employers withhold on a schedule set by your W-4, not on your final tax bill. Over-withholding produces a refund; under-withholding produces a bill in April. Neither changes what you owe.

How to pay less tax in Montana

The largest lever available to most employees is pre-tax retirement contributions. Putting $5,000 into a traditional 401(k) cuts the $85,000 bill by $1,765 in combined federal and Montana tax. That money is not gone — it is yours, moved into a retirement account instead of a tax payment.

Push it to $10,000 and the saving rises to $3,530. At the 2026 contribution limit of $23,500, it reaches $7,776.

An HSA works the same way and is stronger still, because contributions avoid Social Security and Medicare as well as income tax. Both reduce your Montana taxable income too, which is why the saving above is larger than the federal figure alone.

Who pays Montana income tax

Residents of Montana pay on all their income, wherever it was earned. Non-residents pay only on income sourced to Montana — work physically performed there, property located there, business conducted there.

Part-year residents split the year, and the apportionment rules are genuinely fiddly. If you moved during 2026, this calculator will overstate or understate your Montana bill depending on when you moved — it assumes a full year of residency.

Remote work has made this messier. Some states tax income based on where your employer is rather than where you sit, and a handful still apply a "convenience of the employer" rule. If you work across a state line, that question is worth answering before April.

Following $85,000 through the Montana brackets

Start with $85,000 of salary. Montana takes off its standard deduction of $16,100, which leaves $68,900 of taxable income.

That amount does not get taxed at one rate. It gets sliced: 4.70% on $47,500 of it ($2,233); 5.65% on $21,400 of it ($1,209).

Add the slices together and the Montana bill is $3,442. That is 4.05% of the original salary — not the 5.65% of the top slice. The gap between those two numbers is the single most misread thing in state tax.

Retirement income in Montana

Montana is one of only eight states that still tax any Social Security income in 2026 — the others are Colorado, Connecticut, Minnesota, New Mexico, Rhode Island, Utah and Vermont.

Montana taxes Social Security broadly in line with the federal rules, so what is taxable federally is generally taxable here too.

Pensions, 401(k) withdrawals and IRA distributions are taxable in Montana, but not in the way a salary is: the state excludes a slice of them first — up to $5,500 for a single filer and $11,000 for a couple once you reach 65. It is a modest figure, and worth knowing before you count on it.

This is not a pension exclusion but a straight subtraction for anyone 65 or over, whatever the income is. It arrived with the SB 399 simplification that moved Montana onto federal TAXABLE income from 2024, and it is indexed for inflation from 2025.

We have not yet confirmed how Montana treats military retirement pay. Thirty-seven states exempt it, so the odds are it is exempt here too, but we would rather say we have not checked than guess on your behalf.

On the credit side, Montana matches 20% of the federal Earned Income Tax Credit, and it is refundable — you can receive it even with no tax to offset.

The calculator above does not apply any of this — it models salary income with the standard deduction. If a meaningful share of your income is retirement income, treat that figure as an upper bound.

What this Montana calculator leaves out

Being specific about the gaps is more useful than claiming there are none. This figure covers federal income tax, Social Security and Medicare, and Montana state income tax on salary income, using the standard deduction.

itemised deductions beyond the standard one, credits such as the Child Tax Credit and the Earned Income Tax Credit, capital gains, dividends and other investment income, self-employment income and the tax that comes with it, the Alternative Minimum Tax — none of these are in the number above.

If your situation includes any of them, the result here is a starting point, not an answer. That is also why we publish which state figures we have checked against Montana Department of Revenue and which we have not.

What has changed, and what changes next, in Montana

Montana is one of nine states that cut income tax rates as 2025 turned into 2026. We have not yet loaded its full rate history.

The Montana Earned Income Tax Credit

Montana runs its own version of the federal Earned Income Tax Credit, set at 20% of whatever you qualify for federally. It is aimed at working households on lower and middle incomes, and it is claimed on your Montana return rather than applied automatically.

It is refundable, which is the part that matters. A refundable credit pays out even when it exceeds the tax you owe, so a household with little or no Montana tax liability still receives the money. That is what makes a state credit worth having rather than symbolic.

The calculator above does not apply it, because eligibility depends on earned income, filing status and the number of qualifying children rather than salary alone. If you qualify federally, you almost certainly qualify here.

Where Montana sits against similar states

On $85,000, the states closest to Montana are Michigan ($3,362), Oklahoma ($3,280), Georgia ($3,643). If you are weighing a move between any of these, state income tax is not the deciding factor — the gap is smaller than a single pay rise.

The nearest states that charge less are Michigan ($3,362), Oklahoma ($3,280), New Jersey ($3,225) — a saving of up to $217 a year at this salary.

Just above sit Georgia ($3,643), Idaho ($3,652), California ($3,660). And Oregon takes $6,604, $3,162 more than Montana on the same salary.

What five different salaries actually cost in Montana

The single most useful thing to see is how the total moves with income, because it does not move in a straight line. Here is the same calculation at five salaries, single filer, standard deduction:

$45,000 → $8,021 in tax (17.82%), leaving $36,979. $65,000 → $12,904 in tax (19.85%), leaving $52,096. $85,000 → $19,814 in tax (23.31%), leaving $65,186. $120,000 → $32,169 in tax (26.81%), leaving $87,831. $185,000 → $56,347 in tax (30.46%), leaving $128,653.

Between $45,000 and $185,000 the total rate rises by 12.6 points — from 17.82% to 30.46%. That is a smaller jump than most people expect from a salary that has more than quadrupled, and the reason is structural: federal brackets are marginal, so a raise never re-taxes what you already earned, and Social Security stops entirely above $184,500.

Look at the FICA line specifically. At $45,000 it is $3,443, which is 7.65% of gross — more than the $3,220 of federal income tax at that level. At $185,000 it is $14,122, or 7.63%. FICA is the tax that weighs most on modest incomes and least on large ones, and it is the one nobody talks about.

Your marginal rate is not what you pay

On $85,000 in Montana the federal marginal rate is 22.00% — that is what the next dollar costs. What the whole salary actually cost in federal income tax is 11.61%, or $9,870. The gap between those two numbers is the single most misunderstood thing in US tax.

The reason is that brackets are marginal, not cliffs. Only the slice of income inside a bracket is taxed at that bracket's rate. The first $16,100 is not taxed at all, the next slice at 10.00%, and so on up. A pay rise that "pushes you into a higher bracket" never reduces your take-home — that fear is the practical cost of the confusion.

Montana works the same way, with 2 brackets running from 4.70% to 5.65%. On this salary the state marginal rate is 5.65% and the state effective rate is 4.05%.

And there is a third rate that matters more than either: 23.31%, which is everything — federal, FICA, Montana — as a share of gross. That is what actually left your pay. Never compare it against a marginal rate; they measure different things and the comparison suggests an error that is not there.

What your next $10,000 is actually worth here

Going from $85,000 to $95,000 in Montana raises your tax by $3,530, so you keep $6,470 of the $10,000 — an effective rate on the raise of 35.30%. That is the number worth having in a salary negotiation, and it is not the same as either your bracket or your average rate.

Notice that it is higher than your overall effective rate of 23.31%. New income is always taxed at the top, so the marginal cost of a raise exceeds the average cost of everything you already earn. That is the whole point of a progressive system, and it is also why a bonus feels more heavily taxed than a salary — it is stacked on top.

Bonuses have a wrinkle of their own. Employers often withhold them at a flat supplemental rate rather than at your actual marginal rate, which can take more or less than you owe. It comes out right at filing either way, but it explains why a bonus payslip so often looks wrong.

With no local income tax in Montana, the cost of the raise is entirely federal, FICA and Montana.

Five ways this calculation goes wrong

Adding FICA to the withholding. Boxes 4 and 6 of your W-2 are Social Security and Medicare. They are not advance payments of income tax and never come back as a refund. Only box 2 (federal) and box 17 (state) belong in a refund calculation, and including the others overstates it by thousands.

Comparing the effective rate against the marginal rate. Here that would mean setting 23.31% against 22.00% and concluding something has gone wrong. Nothing has: the first includes payroll and state tax, the second is federal income tax on the next dollar. They measure different things.

Assuming a flat state is flat from the first dollar. Ohio taxes nothing below $27,350 of taxable income and Mississippi nothing below $10,000, yet both are widely published as simple flat rates. That single omission overstated Ohio's bill by 43% in the sources we checked.

Assuming your city takes a cut. Montana does not levy an income tax, and only fifteen states permit any city to. Budgeting for one that does not exist is the mirror of the previous mistake.

Using last year's figures. Bracket thresholds, the standard deduction and several state rates are indexed and move every January. Worse, states backdate: Georgia cut its rate in May 2026 with effect from 1 January, so a table published in April was correct when written and wrong by summer. That is why every figure on this site carries the date it was checked.

Deadlines and what you actually have to file in Montana

Federal returns for 2026 are due on 15 April 2027. An extension gives you until 15 October to FILE, but not to PAY — anything owed still accrues interest from April, which is the part people misread. If you expect to owe more than $1,000 beyond withholding, the IRS expects quarterly estimated payments rather than a single settlement.

Montana generally follows the federal calendar, and most states accept the federal extension automatically rather than requiring their own form. Check before assuming: a handful require a separate request, and the penalty for getting it wrong is charged on a bill you may not know you have.

With no local income tax there is no third return to worry about, which is worth something on its own: in states like Ohio and Pennsylvania a working household can face three separate filings a year.

Whatever your situation, the figures on this page are for planning. They assume a salaried filer taking the standard deduction, and they do not model itemised deductions, self-employment income, capital gains, or credits such as the EITC that can change the answer substantially.

Where the Montana figures come from

Federal brackets and the standard deduction come from the IRS Revenue Procedure for 2026, read off the document itself rather than a summary of it.

The Montana figures come from a compiled source and have not yet been read off Montana Department of Revenue. That is stated on the page rather than buried, and it is not a formality: checking states one at a time has already turned up rates that were a year out of date, deductions at half their real value, and one state whose entire structure had been replaced by new legislation.

Every figure carries the date we last verified it, and the full log is published rather than kept internally.

Montana income tax questions

Does Montana have a state income tax?

Yes. Montana has 2 brackets, from 4.70% up to 5.65%.

How much is $85,000 after tax in Montana?

A single filer earning $85,000 in Montana keeps $65,186 for 2026. That is after $9,870 in federal income tax, $6,503 in Social Security and Medicare, and $3,442 in Montana state tax — an effective rate of 23.31% across everything.

What is the top Montana tax rate?

5.65%, and it applies only to taxable income above $47,500. Income below that threshold is taxed at the lower rates.

Why is my Montana tax bill different from this estimate?

This estimate uses the standard deduction and no credits beyond it. Real returns often include state-specific credits, itemised deductions, retirement income exclusions. It is built for planning, not for filing.

How much do I take home per paycheck on $85,000 in Montana?

Paid every two weeks, $2,507 after federal tax, FICA and Montana tax, from a gross of $3,269. Paid monthly, $5,432.

Does contributing to a 401(k) reduce my Montana tax?

Yes. Traditional 401(k) contributions come out before both federal and Montana income tax. On $85,000, contributing $10,000 cuts your combined bill by $3,530.

Is it cheaper to file jointly in Montana?

On $85,000, filing jointly costs $14,874 against $19,814 filing single — $4,940 less. Whether that holds for you depends on both incomes, not just one.