Montana income tax calculator 2026
Montana applies a state individual income tax to ordinary income using a marginal rate system under the current published tax structure. This Montana income tax calculator estimates state tax liability based on the official marginal rates and filing-status-specific income thresholds published by the Montana Department of Revenue, including thresholds for individual filers and certain non-individual filers such as estates and trusts.
Estimates are shown for the 2026 tax year. In cases where official figures have not yet been finalized, calculations are based on the most recently available data and may be updated when final guidance is published.
Annual taxable income for the selected tax year.
Estimated state income tax
Shows an estimated state income tax and an effective rate based on the provided values.
Montana income tax calculator 2026 – how it works
Montana individual income tax is calculated using two marginal rates applied to taxable income. The income thresholds that separate these rates depend on filing status under Montana law. This includes individual filing statuses as well as estates, trusts, and pass-through entity composite filers, which follow the same thresholds as single filers. For each filing category, income within the lower range is taxed at the lower rate, and only the portion above the applicable threshold is taxed at the higher rate. Under the current published rules, Montana taxable income generally starts from federal taxable income and is then adjusted under Montana-specific rules following the state’s tax simplification reforms. Official tax tables and filing guidance are published by the Montana Department of Revenue (https://mtrevenue.gov).
Examples
Under a marginal tax system, income is taxed in layers rather than at a single flat rate. For example, income within the first range is taxed at the lower rate, while only the portion above the applicable threshold is taxed at the higher rate. Although the thresholds differ by filing status, the marginal structure remains consistent across all filer categories recognized in Montana’s published tax tables.
Limitations and important notes
This calculator provides an estimate based on published marginal rates and filing-status-specific thresholds for ordinary income. It does not account for all Montana-specific adjustments that may apply when converting federal taxable income to Montana taxable income, and it does not include the separate net long-term capital gains tax schedule. Final tax liability can differ based on individual circumstances and official filing calculations.
FAQs about Montana income tax calculator 2026
Does Montana use different income tax thresholds by filing status?
Yes. Montana applies the same two marginal tax rates to ordinary income, but the income thresholds at which those rates apply differ by filing status. The official tables also include estates, trusts, and PTE composite filers, which use the same thresholds as single filers.
What marginal tax rates apply to Montana income tax?
Montana applies two marginal tax rates to ordinary income under the current published structure. A lower rate applies to income within the first range, and a higher rate applies only to income above the applicable filing-status threshold.
How is Montana taxable income determined under the current rules?
Under the current rules, Montana generally starts with federal taxable income as the base and then applies Montana-specific adjustments. This reflects the state’s tax simplification reforms enacted under Senate Bill 399.
Does this calculator include Montana’s capital gains tax rules?
No. Montana uses a separate tax schedule for net long-term capital gains under the current published structure. This calculator estimates ordinary income tax only.
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Calculations are simplified and for guidance only. Always double-check results and current rules with official sources or a qualified professional before making financial decisions.