How a Montana paycheck works
Montana rebuilt its withholding from scratch in recent years, and the version in force now is about as simple as a graduated state gets. There are no Montana allowances, no state personal or dependent exemptions, and no state standard deduction to work out. The state schedule is applied to gross earnings directly, with the relief built in as a band at the bottom taxed at nothing. Two rates apply above it.
Federal income tax withholding
Federal withholding annualises the wage, subtracts the standard deduction for the filing status on Form W-4 Step 1, applies the graduated schedule for that status, and deducts the dependent credit from Step 3. This page models a W-4 with Steps 2 and 4 blank: one job, no spouse income, no other income, no extra withholding.
Social Security and Medicare
Social Security takes a flat rate on wages up to an annual ceiling that moves each year. Medicare applies to every dollar, and above a fixed threshold the employer withholds the Additional Medicare tax on the excess.
The nil band is the federal standard deduction
Montana now sets the untaxed band at the bottom of each schedule to the federal standard deduction for that filing status. That is what replaced the state's own exemptions: rather than asking employees to count allowances, the state simply starts taxing above the same threshold the federal return uses. A change to the federal standard deduction therefore moves Montana withholding too, which is unusual among states and worth knowing when federal law changes.
Four boxes on the state certificate, three schedules
The state certificate offers single or married filing separately, married filing jointly, head of household, and a fourth box for a joint filer whose spouse also works. That fourth box does not get its own schedule: it sends the employee onto the single one, because a joint schedule applied to two incomes separately would withhold far too little between them. This page offers that choice for married filers, and it makes a substantial difference.
Rounding
Montana rounds withholding up to the whole dollar rather than to the nearest one. It is a small thing on any one payslip, but it means the state tax shown here is always a whole number and always at or just above the exact figure, never below it.
Local income tax
None. No Montana county or municipality taxes wages, so the state line is the whole of the state and local income tax on a Montana payslip.
What the employer pays on top
The employer matches Social Security and Medicare and pays federal unemployment tax at its net rate. Montana unemployment insurance is an employer contribution at an experience-rated percentage on a state wage base, alongside an administrative fund assessment. There is no employee-side state levy: no disability insurance, no paid leave premium.
What this calculator assumes
The figure models a salaried employee paid evenly across the year with a standard Form W-4 and state certificate, and no pre-tax deductions. It leaves out:
- Pre-tax contributions such as a 401(k), health premiums, HSA or flexible spending accounts.
- Extra withholding requested on the state certificate, and the W-4 Step 2 and Step 4 adjustments.
- Bonuses and other supplemental wages, which may be withheld differently.
- Employer-side Montana unemployment insurance and the administrative fund assessment.
- Capital gains, which Montana taxes at its own lower rates on the annual return but which do not pass through payroll.
Withholding versus your final tax bill
Withholding is a prepayment. The federal and Montana returns replace these assumptions with your real situation: itemised deductions, other income, and credits payroll knows nothing about, including Montana's earned income credit, which is set as a share of the federal one. A household entitled to that credit is likely to find the return returns money.