Who pays the alternative minimum tax?

What the AMT is

Publication 17 describes the alternative minimum tax as an additional tax you may have to pay. The tax law gives special treatment to some kinds of income and allows special deductions and credits for some kinds of expenses. Taxpayers who benefit from this special treatment may have to pay at least a minimum amount of tax through the AMT. The Form 6251 instructions say the same thing from the other side: the AMT is a separate tax imposed in addition to your regular tax, and it sets a limit on how much those benefits can reduce your total tax.

Think of it as a parallel return. You compute your tax the regular way, then recompute it with a different set of income and deduction rules and a different rate schedule. If the second answer is larger, you pay the difference as AMT, on top of the regular tax.

Who actually pays it

Pub. 17 says you may have to pay the AMT if your taxable income for regular tax purposes, combined with certain adjustments and tax preference items, is more than a certain amount. The Form 6251 instructions give the filing test: attach Form 6251 to your return if Form 6251, line 7, is greater than line 10, which in plain terms means your tentative AMT figure is more than your regular tax. There are other triggers too, such as claiming certain credits (the general business credit, the qualified electric vehicle credit, the credit for prior year minimum tax and others), or having negative adjustments that would otherwise hide an AMT liability.

In practice the people who run into AMT are those with large amounts of the items below: exercised incentive stock options, large state and local tax deductions, significant tax-exempt private activity bond interest, or depreciation and passive-activity differences. Pub. 17 gives no count of who owes it, and a household without these items is not affected by them.

The common adjustments and preference items

Pub. 17 lists the more common items: addition of the enhanced senior deduction; addition of the standard deduction if claimed; addition of itemized deductions claimed for state and local taxes and certain interest; subtraction of any refund of state and local taxes included in gross income; changes to accelerated depreciation of certain property; the difference between gain or loss on the sale of property for regular and AMT purposes; addition of certain income from incentive stock options; a change in certain passive activity loss deductions; addition of certain depletion more than the adjusted basis of the property; addition of part of the deduction for certain intangible drilling costs; and addition of tax-exempt interest on certain private activity bonds.

The first two are why a taxpayer with a large standard deduction can still be exposed: the AMT adds the standard deduction back, then gives you an exemption instead.

The 2025 numbers

The Form 6251 instructions for 2025 give these figures. The exemption amount is $88,100 if single or head of household, $137,000 if married filing jointly or a qualifying surviving spouse, and $68,500 if married filing separately. The exemption phases out at 25 cents per dollar once alternative minimum taxable income passes $626,350 ($1,252,700 if married filing jointly or a qualifying surviving spouse). It disappears at $978,750 for single and head of household, $1,800,700 for joint filers and $900,350 for married filing separately. For noncorporate taxpayers the 26% rate applies to the first $239,100 ($119,550 if married filing separately) of the taxable excess; above that the rate is 28%, which the worksheet implements as 28% of the amount minus $4,782 ($2,391 for married filing separately).

Worked examples

Single, AMTI $400,000, regular tax $70,000. The exemption is the full $88,100 because $400,000 is under the $626,350 phaseout start. The taxable excess is $311,900. Because it is over $239,100, tentative minimum tax is 28% × $311,900 − $4,782 = $87,332 − $4,782 = $82,550. Subtract regular tax of $70,000 and the AMT is $12,550.

Single, AMTI $800,000. Phaseout reduces the exemption by 25% of ($800,000 − $626,350) = $43,412.50, leaving $44,687.50. Taxable excess is $755,312.50 and the tentative minimum tax is $206,705.50.

Married filing jointly, AMTI $150,000, regular tax $12,000. The exemption is $137,000, the excess is $13,000, and 26% of that is $3,380, which is less than regular tax, so no AMT is due. The calculator above runs these cases; it covers ordinary income only, and it ignores capital gain rates, foreign earned income and credits, which Form 6251, Part III, handles.

Limits and next steps

The estimator is a teaching tool. Your real AMTI comes from Form 6251, Part I, and the instructions are long because each adjustment has its own computation. If you exercised incentive stock options, owe state tax on a large income, or hold private activity bonds, run the real form or have a preparer do it. Related tools: the AMT exemption calculator for 2026, the federal income tax calculator for your regular tax, the capital gains tax calculator and the brackets.

Sources

• IRS Publication 17, Your Federal Income Tax (2025): Alternative Minimum Tax (AMT) in chapter 13, How To Figure Your Tax. Read November 2, 2026.
• IRS Instructions for Form 6251 (2025): What's New (AMT exemption, phaseout and tax brackets); Who Must File; Purpose of Form; Exemption Worksheet, Line 5; Line 7 tax computation. Read November 2, 2026.

Edition read: Publication 17 (2025), Your Federal Income Tax, for use in preparing 2025 returns. Dollar limits and dates are for the 2025 tax year unless the text says otherwise; check the current publication and form instructions for your tax year. This page summarizes the publication and does not replace it.