AMT Calculator (Alternative Minimum Tax) United States

What the AMT calculator does

The Alternative Minimum Tax calculator estimates whether the AMT adds to your federal tax bill for the 2026 tax year, and by how much. It takes your alternative minimum taxable income, applies the exemption for your filing status, taxes the rest at the 26 and 28 percent AMT rates, and compares the resulting tentative minimum tax with the regular federal income tax you expect to pay. If the tentative minimum tax is higher, the difference is the AMT you owe on top of your regular tax. If it is lower, you owe no AMT.

The AMT runs alongside the regular rules so that high earners who claim large deductions and preference items still pay a minimum amount of tax. To know where you stand you have to compute both and take the larger figure, and the calculator does that comparison.

How the alternative minimum tax works

• It starts from your alternative minimum taxable income (AMTI), which is your income recomputed under AMT rules.
• It subtracts the AMT exemption for your filing status, reduced by any phaseout.
• It taxes the remaining AMT base at 26 percent up to the annual breakpoint and 28 percent above it, producing the tentative minimum tax.
• It subtracts your regular federal income tax; anything left over is the AMT you owe.

With a large exemption and only two rates, the AMT has a very different shape from the graduated regular brackets. Taxpayers whose regular tax is well above the tentative minimum tax never trigger it. It becomes relevant for filers with high income plus items that lower regular tax but not AMT income.

The exemption and its phaseout

The AMT exemption is the amount of AMTI shielded before the 26 percent rate applies. For 2026 the single exemption is $90,100, and it is larger for married couples filing jointly. The exemption is what keeps the AMT away from most households.

Once AMTI passes the phaseout threshold, each dollar above it reduces the exemption by 50 cents. That is faster than under the previous rules, so a high earner can lose the exemption entirely and be taxed on the full AMT base. This is why the AMT can jump sharply over a fairly narrow income range, and the calculator shows how much of the exemption is left at your income.

Reading your result

The output leads with the AMT owed, the extra tax beyond your regular liability. Below it are the tentative minimum tax and the exemption that went into it, so you can trace how the figure was built.

Zero AMT owed is common and means your regular tax already exceeds the tentative minimum tax. A positive figure means the AMT applies to you, and you should look at which items pushed your AMTI up. Comparing tentative minimum tax with regular tax shows how close you are to the point where the AMT starts.

Worked example

Consider a single filer with $300,000 of AMTI and $40,000 of regular federal tax. The income is below the $500,000 phaseout threshold, so the full $90,100 exemption applies, leaving an AMT base of $209,900. That base is below the $244,500 breakpoint, so all of it is taxed at 26 percent, giving a tentative minimum tax of $54,574. Since that exceeds the $40,000 regular tax, the AMT owed is $14,574.

Now raise the AMTI to $800,000. The income is $300,000 above the phaseout threshold, so the exemption is cut by 50 cents per dollar, a $150,000 reduction that removes the $90,100 exemption completely. The AMT base is the full $800,000. The first $244,500 is taxed at 26 percent and the remaining $555,500 at 28 percent, for a tentative minimum tax of $219,110. Against $150,000 of regular tax, the AMT owed is $69,110.

Assumptions and limitations

This calculator is a planning estimate, not a tax return. It assumes you can supply your alternative minimum taxable income and your regular federal tax; working those out precisely means going through the AMT preference items, adjustments, and any AMT credits on a full return. It uses the 2026 exemption amounts, phaseout thresholds, and 26 and 28 percent rates, which are indexed and change from year to year.

It does not model the AMT treatment of capital gains and qualified dividends, foreign tax credits, or the minimum tax credit carryforward, all of which can change the final number. Use the result to judge whether the AMT is likely to matter for you, then confirm the details with a tax professional.

This is general information only and not financial advice.

About This AMT Calculator

Use this AMT calculator to get an instant, accurate estimate. The figures follow official IRS guidance and every rate and threshold is kept up to date for 2026. Adjust the inputs above to match your situation, or browse all our calculators to plan your next step.