Tax year 2026

Alternative Minimum Tax Calculator

Computes Form 6251 including Part III, so long-term gains and qualified dividends keep their preferential rates rather than being taxed at 26 or 28 percent. Shows whether AMT actually applies, and your effective marginal rate inside the exemption phaseout.

Filing status
From your return
Form 1040, line 15.
Form 1040, line 16. AMT is the amount by which tentative minimum tax exceeds this, so the comparison needs your real figure.
The portion of the taxable income above that is long-term capital gain or qualified dividends. These keep their 0/15/20% rates under AMT — leaving this blank will substantially overstate your AMT if you had a large gain.
AMT adjustments & preferences

Actual dollar amounts. Leave blank where they do not apply.

Form 6251 line 2a. The entire deduction is added back, not just the portion above the regular cap. Leave blank if you took the standard deduction and enter it below instead.
Form 6251 line 2i. Shares exercised × (fair market value at exercise − strike price), for options exercised and still held at year end.
Form 6251 line 2g. Tax-exempt for regular tax, a preference item here.
Standard deduction if you claimed it, depletion, intangible drilling costs, and the remaining Form 6251 lines 2b through 3.

Not modelled: the 3.8% net investment income tax, the AMT foreign tax credit, AMT net operating losses, depreciation adjustments, and the AMT basis difference on ISO shares in the year you sell them. Any of those can move the answer.

Your result

$0

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    Your figures line by line, plus the timing moves that actually reduce AMT exposure — and what has to happen before December 31 rather than in April.

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    For professionals

    We build client-ready versions of these models for planning meetings — branded to your firm, with your assumptions. Tick the box above and we will include the details.

    This calculator provides estimates for educational purposes only and is not tax, legal or investment advice. It implements Form 6251 Parts I through III but does not model the net investment income tax, the AMT foreign tax credit, AMT net operating losses, depreciation adjustments, AMT basis differences on the sale of ISO shares, or any state alternative minimum tax. Confirm every figure with a qualified tax professional before acting on it. Constants reflect IRS Rev. Proc. 2025-32 and IRC §55 as amended by OBBBA §70107.

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