Free alternative minimum tax (amt) calculator
Enter your taxable income and deductions — this AMT calculator applies the 2024 exemption ($85,700 single / $133,300 MFJ) and 26%/28% rate to estimate whether you owe Alternative Minimum Tax, updated live, as you type.
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Estimated only. Actual withholding depends on your W-4 elections, filing status, and local laws. Consult your payroll provider for exact figures.
Results are estimates. Consult a professional.
How the AMT calculator works
The Alternative Minimum Tax (AMT) is a parallel federal income tax designed to ensure that high-income taxpayers pay at least a minimum amount of tax, regardless of deductions and credits. You calculate your tax twice — once under the regular rules and once under the AMT rules — then pay whichever amount is higher.
AMT starts with your regular taxable income, adds back certain items that are deductible under regular rules but not under AMT (called preferences and adjustments), then subtracts an AMT exemption. The result is your Alternative Minimum Taxable Income (AMTI), to which flat AMT rates are applied.
Worked example: ISO exercise triggering AMT
Alex and Jordan file jointly. Their regular taxable income before the ISO exercise is $180,000. Alex exercises incentive stock options (ISOs) with a spread of $300,000. The spread is an AMT preference item — not in regular income, but fully included in AMTI. 2024 MFJ exemption: $133,300.
2024 AMT exemption and phase-out thresholds
The AMT exemption is inflation-adjusted each year. The phase-out reduces the exemption by $0.25 for each dollar of AMTI above the threshold, effectively eliminating the exemption entirely at higher income levels.
| Filing status | AMT exemption | Phase-out begins | Exemption fully gone at |
|---|---|---|---|
| Single / HOH | $85,700 | $609,350 | $952,150 |
| Married filing jointly | $133,300 | $1,218,700 | $1,751,900 |
| Married filing separately | $66,650 | $609,350 | $875,950 |
Source: IRS Rev. Proc. 2023-34 (2024 inflation adjustments). Phase-out rate: $0.25 exemption lost per $1.00 of AMTI above threshold.
| AMTI over exemption | AMT rate |
|---|---|
| $0 – $232,600 | 26% |
| Over $232,600 | 28% |
The $232,600 bracket applies to all filing statuses except MFS, which uses $116,300. Source: IRS Form 6251 (2024).
Tips for managing your AMT exposure
The AMT most commonly catches taxpayers by surprise when they exercise ISOs, have large state and local tax deductions, or claim significant accelerated depreciation. The strategies below can reduce or defer your AMT liability.
- Exercise ISOs strategically — The ISO spread is the single biggest AMT trigger. Spread exercises across multiple tax years to stay below AMT exposure, or sell in the same year (a 'disqualifying disposition') to convert the gain to ordinary income and remove the AMT preference entirely.
- Time your SALT payments — State and local income and property taxes are allowed under regular tax but fully disallowed under AMT. If AMT already applies, prepaying SALT has zero benefit.
- Use the AMT credit in future years — Any AMT you pay due to deferral preferences (like ISOs) creates a minimum tax credit (Form 8801) you can apply in future years when your regular tax exceeds your tentative minimum tax.
- Run a parallel AMT projection — Because certain deductions and credits work differently under AMT, always model your return under both systems before year-end to spot surprises while there is still time to act.
- Watch depreciation adjustments — Accelerated MACRS depreciation claimed on business property must often be recalculated using ADS (slower) lives under AMT; the difference is an AMT adjustment added back to income.
Accuracy and limitations
This calculator estimates your tentative minimum tax using your stated taxable income plus any additional AMT preferences and adjustments you enter, the 2024 AMT exemption for your filing status, and the statutory 26%/28% rate schedule. It then compares the result to your regular federal income tax to estimate net AMT owed.
The tool does not model every AMT adjustment (e.g., passive activity loss differences, long-term contract income, pollution-control amortization) or the interaction with foreign tax credits. The actual AMT calculation is completed on IRS Form 6251 and may differ from this estimate. This calculator is a planning tool only — not tax advice. Verify all figures with IRS Form 6251 and a qualified tax professional.
AMT terms defined
About this AMT calculator
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