US federal AMT estimate — tentative minimum tax versus regular tax, with editable 2025 figures.
Regular taxable income plus AMT add-backs (e.g. state/local tax deduction, some deductions and preferences).
Your tax under the regular rules, before AMT.
Default $88,100 (single, 2025). Married-joint 2025 default is $137,000 — change this field if that applies.
Default $626,350 (single, 2025); married-joint 2025 is $1,252,700. Above it the exemption phases out at 25 cents per dollar.
Default $239,100 (2025). AMT is 26% up to this taxable excess, 28% above it.
US federal estimate only — not tax advice. Exemption figures are editable and default to widely published 2025 figures; figures change yearly — verify the year that applies to you.
additional AMT owed (tentative AMT − regular tax)
How to use this tool
Start from regular taxable income and add back AMT adjustments (state/local taxes deducted, certain deductions and preferences). This calculator takes AMTI as its input.
Type the federal tax computed under the ordinary rules, before any AMT.
Defaults are widely published 2025 figures. If you file jointly, set the exemption to $137,000 and the phase-out to $1,252,700; for other years, update all three editable figures.
You pay the higher of regular tax and tentative minimum tax — the difference, if any, is the AMT owed.
Formula & worked example
Worked example: AMTI $400,000, regular tax $70,000, single 2025 exemption $88,100 (no phase-out at this income), breakpoint $239,100. AMT base = $311,900; tentative tax = 26% × $239,100 + 28% × $72,800 = $62,166 + $20,384 = $82,550. Additional AMT owed = $82,550 − $70,000 = $12,550.
Limitations — read this before you rely on it
US federal estimate only, not tax advice. AMTI itself is a complex computation (add-backs, adjustments, preferences, credits); this calculator takes AMTI as given and does not compute it from a tax return. Exemption, phase-out and breakpoint figures change most years — the defaults are 2025 figures and must be checked for your tax year. State AMT rules are separate.
Frequently asked questions
A parallel US federal tax system. You compute tax under both the regular rules and the AMT rules (with fewer deductions and a large exemption) and pay whichever is higher.
Historically high earners with large deductions, especially state/local taxes, and people exercising incentive stock options. Since the 2017 tax law raised the exemption, far fewer taxpayers owe it.
AMT exemption, phase-out and the 26%/28% breakpoint change most years. The defaults here are widely published 2025 figures; always verify the figures for your own tax year.
Some states have their own AMT-like taxes with different rules. This calculator covers US federal AMT only.
Sometimes — AMT paid on timing items (like ISO exercises) can generate a minimum tax credit in later years. That credit computation is outside this calculator.