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    Tax / Federal

    Alternative Minimum Tax Calculator

    The AMT runs a parallel calculation: add back the preferences, subtract an exemption that phases out at high income, apply 26 % and 28 %, and pay the excess over regular tax. The 2026 exemption and phase-out are from Rev. Proc. 2025-32.

    AMT owed$0.00Exemption$140,200AMT base$259,800
    AMT owed
    $0.00
    Regular tax is higher
    Exemption
    $140,200
    Phases out above $1,000,000
    AMT base
    $259,800
    AMTI minus exemption
    Tentative tax
    $67,854
    26 % / 28 % above $244,500
    AMT computation
    The order matters: exemption, base, tentative tax, then the excess over regular tax.
    AMT computation
    TermAmount
    AMTI$400,000
    Exemption$140,200
    AMT base$259,800
    Tentative minimum tax$67,854
    Regular tax$70,000
    AMT owed$0.00

    The exemption falls by 25 cents for every dollar of AMTI above the phase-out start.

    Inspect the model
    Choose a quick result view, a scaled comparison, or the complete diagnostic set.
    AMT owed against AMTI
    The flat stretch is the phase-out; the slope is the 28 % rate.
    AMT owed against AMTI0.0003.715e+47.430e+41.115e+51.486e+51.858e+5$0.00$0.00$100,000$100,000$200,000$200,000$300,000$300,000$400,000$400,000$500,000$500,000$600,000$600,000$700,000$700,000$800,000$800,000$900,000$900,000$1,000,000$1,000,000AMT owed
    Canonical equations
    The exact relationships implemented by this engine.

    max(0, exemption − 25 % × (AMTI − phase-out start)) · Rev. Proc. 2025-32 §3.10.

    26 % × base up to threshold + 28 % above · Threshold $244,500.

    max(0, tentative − regular tax) · A parallel system, not a surcharge.

    finance methodology

    A clear path from inputs to results.

    The AMT runs a parallel calculation: add back the preferences, subtract an exemption that phases out at high income, apply 26 % and 28 %, and pay the excess over regular tax. The 2026 exemption and phase-out are from Rev. Proc. 2025-32.

    Step-by-step methodWorked exampleAssumptions explained

    How to use

    1. Set alternative minimum taxable income.
    2. Set filing status.
    3. Set regular federal tax.
    4. Read the headline metrics, then check the table for the detail.

    The formula

    AMT=max⁡(0,  Tmin−Treg)AMT = \max(0,\; T_{min} - T_{reg})

    Reference: IRS Rev. Proc. 2025-32 §3.10 (2026 exemption, phase-out and 28% threshold).

    Worked example

    At the default inputs

    Inputs
    • Alternative minimum taxable income: 400000; Filing status: mfj; Regular federal tax: 70000
    Calculation path
    1. 1

      Phase the exemption → $140,200 Apply 26/28 → $67,854 Compare to regular → $0.00

    Result

    AMT owed: $0.00 · Exemption: $140,200 · AMT base: $259,800

    Interpreting the result

    On $400,000 of AMTI a MFJ filer has a $140,200 exemption, a $67,854 tentative minimum tax, and no AMT after $70,000 of regular tax.

    Assumptions & limitations

    • AMTI is entered directly; adjustments and preferences are not itemised.
    • Regular tax is entered directly.
    • The 26%/28% rates apply to the AMT base.

    Frequently asked questions

    Is AMT an extra tax?

    No. It is the excess of the tentative minimum tax over regular tax.

    Why does the exemption fall?

    It phases out at 25 cents per dollar of AMTI above the threshold.

    Methodology last reviewed 2026-10-23. Results are informational and not financial or engineering advice — see our disclaimer.