Free AMT calculator. Estimate your Alternative Minimum Tax for 2025 based on income, preference items, and exemption amounts. See if you are subject to AMT.
The Alternative Minimum Tax (AMT) Calculator estimates whether you may owe AMT and how much. The AMT is a parallel tax system that ensures taxpayers with significant deductions or preference items pay at least a minimum amount of tax.
The AMT recalculates your tax by adding back certain deductions (like SALT, ISO exercises, and private activity bond interest) and applying a 26% or 28% rate to the result, then compares this to your regular tax. You owe AMT only if the AMT calculation exceeds your regular tax.
For 2025, the AMT exemption is $88,100 (single) or $137,000 (MFJ). The exemption phases out at higher income levels. Enter your details to see whether AMT applies and what additional tax you may owe. AMT primarily affects taxpayers with large state and local tax deductions, significant capital gains, or incentive stock option exercises. Understanding your AMT exposure before year-end gives you time to adjust timing of income and deductions to minimize the impact.
AMT can catch high-income taxpayers by surprise, especially those exercising ISO stock options, claiming large SALT deductions, or earning income from private activity bonds. This calculator flags AMT exposure before filing so you can plan accordingly. Early detection gives you the opportunity to adjust your year-end tax strategy and potentially reduce or eliminate the additional liability.
AMTI = Taxable Income + AMT Preference Items (SALT, ISO spread, etc.) AMT Exemption (2025): $88,100 (single) / $137,000 (MFJ) Exemption Phase-Out Start: $609,350 (single) / $1,218,700 (MFJ) Exemption reduced by 25¢ per $1 over phase-out start AMT Base = AMTI – Exemption Tentative Minimum Tax = 26% on first $248,300 ($124,150 MFS) + 28% on excess AMT Owed = Max(0, Tentative Minimum Tax – Regular Tax)
Result: AMTI: $365,000 | AMT owed: $7,494
Taxable income $300,000 + $15,000 SALT addback + $50,000 ISO spread = $365,000 AMTI. AMT exemption $88,100 (no phase-out yet). AMT base = $365,000 – $88,100 = $276,900. Tentative minimum tax = $248,300 × 26% + $28,600 × 28% = $64,558 + $5,008 = $69,494 (approx). AMT owed = $69,494 – $62,000 = $7,494.
The AMT runs parallel to the regular tax. Your actual tax is the higher of the two. The AMT uses a broader income definition (AMTI) and only two rates (26% and 28%), compared to seven regular brackets (10%-37%). The AMT exemption partially compensates, but phases out for high earners.
Exercising incentive stock options can trigger substantial AMT because the spread (market price minus exercise price) is an AMT preference item. Strategies include exercising in stages across multiple tax years, exercising when the spread is small, or exercising and selling in the same year (disqualifying disposition) to avoid AMT.
If you pay AMT due to timing items like ISOs, you accumulate an AMT credit that reduces future regular tax. The credit can be carried forward indefinitely. This is an important recovery mechanism — keep track of your AMT credit carryforward on Form 8801.
The AMT is a parallel tax system that limits certain deductions and adds back preference items to ensure high-income taxpayers pay at least a minimum amount of tax. It applies two rates (26% and 28%) to a broader income base. You owe AMT only when the tentative minimum tax exceeds your regular income tax.
Common preference items include: state and local tax (SALT) deductions, the bargain element from exercising incentive stock options (ISOs), tax-exempt interest from private activity bonds, accelerated depreciation differences, and certain passive activity losses. These items are added back to regular taxable income to calculate AMTI.
For 2025, the AMT exemption is $88,100 for single filers, $137,000 for married filing jointly, and $68,500 for married filing separately. The exemption begins to phase out at $609,350 (single) and $1,218,700 (MFJ), reducing by 25 cents for every dollar above the threshold.
Taxpayers most likely to owe AMT include those who exercise large amounts of ISOs, claim large SALT deductions, have significant private activity bond income, or have high income with many deductions. The risk is highest for income between $200,000 and $500,000.
Yes, if your AMT was caused by timing differences (like ISO exercises that create a temporary AMT adjustment), you can claim an AMT credit in future years when your regular tax exceeds the tentative minimum tax. This credit helps recover AMT paid on timing items.
The AMT exemption is reduced by 25 cents for every dollar of AMTI above the phase-out threshold ($609,350 single / $1,218,700 MFJ). This means the exemption is completely eliminated when AMTI exceeds $961,750 for single filers or $1,766,700 for MFJ.