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State Tax Savings and Exposure Calculator
Enter your income and pick two states. See the estimated state income tax delta from 2026 bracket data, then see what it actually takes to make that savings survive an audit.
General information, not tax or legal advice. See methodology and sources below.
Calculator
Compare state income tax between two states.
Leaving Montana
$12,764
estimated annual state income tax
Montana taxes this income at a top marginal rate of 5.65% under its bracket schedule.
Marginal rate: 5.65% · Effective rate: 5.11%
Moving to Pennsylvania
$7,675
estimated annual state income tax
Pennsylvania taxes income at a flat 3.07% rate after its standard deduction.
Marginal rate: 3.07% · Effective rate: 3.07%
Moving from Montana to Pennsylvania would save an estimated $5,089 per year in state income tax at this income.
That is roughly $424 per month at this income and filing status.
Savings only survive an audit you can win.
Montana does not use a fixed day count. It weighs a closest-connections and domicile test instead. Here is what Montana would need to see before an exit claim survives an audit.
Montana is not named among the states practitioners and taxpayers consistently flag as aggressive on residency (California, New York, New Jersey, Connecticut, Maryland, Minnesota), and no publicly documented large-scale departing-resident audit program was found. Montana's cross-purpose residence rule, however, creates a specific, self-inflicted risk: because claiming Montana residency for any purpose (a hunting license, a homestead declaration, in-state college tuition) can be read as claiming it for all purposes absent a statutory exception, a person who has genuinely moved but still claims a Montana-resident benefit somewhere else in the system hands the Department (or their old or new home state) direct evidence against their own position.
Statute of limitations
5 years from the date the return was filed, per Mont. Code Ann. §15-30-2605, notably longer than the 3-to-4-year window most neighboring states use. There is no limitation period if a required return, including a federal adjustments report, was never filed.
Defense cost range
No published figures specific to Montana residency-audit defense were found. Practitioners describe Montana as a low-audit-intensity state relative to California or New York, but no firm dollar range has been published.
What Montana checks
Common exit mistakes
Popular corridors
California to Arizona
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Load this comparisonHow the estimate is built
Each state's bracket schedule, standard deduction, and no-tax or flat-tax status come from data/residency/tax-tables.json, a 2026 tax year table compiled 2026-08-05 and sourced primarily from the Tax Foundation, cross-checked against state revenue agency pages.
The calculator subtracts the standard deduction from your entered income, then applies the state's marginal bracket schedule (or its single flat rate, or $0 for the nine states with no income tax) to what remains. It does not model itemized deductions, credits, local income taxes, or capital gains treatment that differs from ordinary income.
Puerto Rico, the U.S. Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands run regimes that cannot be reduced to a single bracket rate honestly, so the calculator explains why instead of guessing.
Why the exposure panel matters
A lower number on a calculator only becomes real money if your former state agrees you actually left. High-tax states with aggressive enforcement audit departing high earners on domicile, not just day counts: family location, retained property, financial relationships, and the timing of the move relative to a liquidity event.
The exposure panel pulls your origin state's exit audit risk, enforcement methods, common exit mistakes, statute of limitations, and audit aggressiveness directly from its researched dossier, the same data behind the full state guide.
See all 56 state and territory guidesFrequently asked questions
How accurate is this state tax calculator?+
The calculator applies each state's actual published 2026 income tax brackets and standard deduction from data/residency/tax-tables.json, sourced primarily from the Tax Foundation and cross-checked against state revenue agency pages. It is a planning estimate, not a filing: it does not account for itemized deductions, credits, local or city income taxes, or income other than ordinary wage-style income.
Does this include local or city income taxes?+
No. The figures shown are state-level income tax only. Some cities layer their own income tax on top of the state figure (New York City is the best-known example), so your actual bill in a city with a local tax will be higher than what this tool shows.
Why can't I get a dollar estimate for Puerto Rico, Guam, or the other territories?+
The five U.S. territories do not run state-style bracket tables. Puerto Rico has its own separate tax code plus a decree-based Act 60 incentive program, and the U.S. Virgin Islands, Guam, and the Northern Mariana Islands mirror the federal code with local filing instead of state brackets. Reducing any of these to one calculator rate would misstate the actual regime, so the tool shows an honest explanation instead of a fabricated number. Use the jurisdiction guide for the real rules.
If the calculator shows savings, is that savings guaranteed?+
No. A state income tax bill only drops if your residency change actually holds up under audit. States with aggressive enforcement, especially high-tax states losing a high earner, look closely at whether your domicile genuinely moved: where your family lives, where you spend your time, and whether you kept ties like a home, doctors, or bank relationships behind. That is what the exposure panel below the calculator explains for your origin state.
Does this account for capital gains, stock options, or business income?+
The calculator applies each state's general income tax brackets, which most states tax the same as ordinary income (a few exceptions are noted on the state guides). It does not model deferred compensation, stock vesting schedules, or business income sourcing rules, all of which several states keep taxing after you leave under trailing-income rules. Check your origin state's guide for its specific trailing-income treatment before assuming a move date changes when that income is taxed.
What income figure should I enter?+
Enter your expected annual gross income (wages, salary, and similar ordinary income). The calculator subtracts each state's standard deduction automatically to estimate taxable income, then applies that state's bracket schedule. It does not know about your itemized deductions, pretax retirement contributions, or credits, so treat the result as a starting estimate rather than a completed return.
Methodology and sources
Tax figures: 2026 state individual income tax brackets and standard deductions from data/residency/tax-tables.json, compiled 2026-08-05, sourced primarily from the Tax Foundation's state income tax rates publication and cross-checked against individual state revenue agency pages.
Exposure figures: each state's exit audit risk, enforcement methods, statute of limitations, and audit aggressiveness come from that state's researched dossier at data/residency, with sources listed on the corresponding state guide.
ResidencyIQ organizes public tax and residency research into a reviewable estimate. It does not provide legal, tax, or accounting advice. Consult a qualified professional before making a residency decision or filing a return.
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