The Alternative Minimum Tax: A Separate Tax on Some Higher Incomes
Published November 5, 2026
The alternative minimum tax (AMT) is a separate tax. It applies to some taxpayers who use certain tax benefits. The benefits can reduce regular tax a lot. The AMT sets a limit on how far they can reduce total tax. IRS: Topic no. 556, Alternative Minimum Tax
How the AMT works
The AMT is the amount by which the tentative minimum tax is more than your regular tax. So you owe AMT only when the tentative minimum tax is greater than your regular tax for the year. The tentative minimum tax is figured separately. IRS: Topic no. 556
To figure it, you start with taxable income and adjust certain items. Then you subtract the AMT exemption amount. Then you apply the AMT tax rates. Last, you subtract the AMT foreign tax credit. IRS: Topic no. 556
The 2025 exemption amounts
For 2025, the AMT exemption is $88,100. For married filing jointly or a qualifying surviving spouse, it is $137,000. For married filing separately, it is $68,500. The exemption starts to phase out when alternative minimum taxable income is above $626,350. For married filing jointly, that amount is $1,252,700. IRS: 2025 Instructions for Form 6251
For 2025, the 26% AMT rate applies to the first $239,100 of taxable excess for most noncorporate taxpayers. For married filing separately, the amount is $119,550. IRS: 2025 Instructions for Form 6251
Who must file Form 6251
You attach Form 6251 to your return if your AMT line is greater than your regular tax line. You also attach it if you claim certain credits, such as the general business credit or the credit for prior year minimum tax. IRS: 2025 Instructions for Form 6251
Common items that differ for the AMT
Some items are figured differently for the AMT. Examples include certain taxes from Schedule A, investment interest, and some business and rental items. The IRS lists carryovers that can differ too, such as a net operating loss, a capital loss, a passive activity loss, and the foreign tax credit. Each may have a separate amount for the AMT. IRS: 2025 Instructions for Form 6251
The AMT is a separate tax that is imposed in addition to your regular tax. Form 6251 also figures your tentative minimum tax, which can matter when some credits are limited. The standard deduction is not allowed for the AMT. If you owe AMT, itemizing may lower your total tax, even if your itemized deductions are less than the standard deduction. IRS: 2025 Instructions for Form 6251
Prior-year minimum tax credit
If you paid AMT in an earlier year, you may be able to take a credit for it on Form 8801 in a later year. This credit is for a year when you owe no AMT. IRS: Topic no. 556
Illustration only, with made-up numbers. Sam is single. Sam's alternative minimum taxable income for 2025 is $100,000. That is above the $88,100 exemption, so the amount above it is taxable at AMT rates. Sam must compare the AMT with regular tax. Sam owes AMT only if the AMT is larger. Phaseout rules do not apply, since $100,000 is below $626,350.
Records to keep
Keep records that show how you figured your AMT items. Keep a copy of any AMT version of a form or worksheet. Keep records of carryovers and basis that differ between the AMT and regular tax. IRS: 2025 Instructions for Form 6251
Steps to take
- Find your regular tax and your alternative minimum taxable income for 2025.
- Check the 2025 exemption amount for your filing status.
- Compare the tentative minimum tax with your regular tax.
- If Form 6251 is required, complete it and attach it to your return.
- Keep records for any items that are different for the AMT.
General information, not advice about your return.
Sources: Sources: IRS, Topic no. 556, Alternative Minimum Tax (https://www.irs.gov/taxtopics/tc556); IRS, 2025 Instructions for Form 6251 (https://www.irs.gov/pub/irs-pdf/i6251.pdf) This is general information, not advice about your specific return.
