AMT Calculator
Calculate your Alternative Minimum Tax (AMT) liability based on income, SALT deductions, ISO stock option exercises, and filing status using current-year federal brackets and 2024 AMT exemption parameters.
About this calculator
This calculator runs two parallel tax calculations and makes you pay the higher one. Regular Tax uses the current-year federal brackets (computeFederalTax) against income minus the standard deduction. AMT starts from AMT Income (AMTI) -- total income minus the standard deduction, plus State & Local Taxes capped at $10,000 added back (since AMT doesn't allow the SALT deduction regular tax gets), plus ISO Exercise Spread and Other AMT Preferences added in full -- then subtracts an AMT exemption ($85,700 single / $133,300 MFJ) that phases out 25 cents per dollar once AMTI exceeds $609,350 single / $1,218,700 MFJ, and taxes the result at 26% up to $232,600 and 28% above. AMT Owed is the excess of that tentative minimum tax over your regular tax, floored at zero. These AMT exemption and phase-out figures are pinned to 2024 (IRS Rev.
Proc. 2023-34) in the engine's own AMT_PARAMS constant -- a code comment flags that no AMT module exists yet in the shared statutory reference-data, so they have not been re-verified against a canonical current-year source and will not update automatically, unlike Regular Tax, which does use the current-year bracket table. Total Income moves Total Federal Tax and AMT Income directly, but Filing Status dominates AMT Exemption Used outright since it selects between two entirely different exemption tables. State & Local Taxes has no effect on Regular Tax at all in this model -- regular taxable income is computed using the standard deduction only, never itemized SALT -- so it only matters for the AMT side, and only up to the $10,000 add-back cap. ISO Exercise Spread is the input that typically triggers AMT for tech employees; at this calculator's defaults it's zero and AMT Owed comes out to $0.
Tax Disclaimer
This calculator provides estimates based on general tax rules and may not reflect your specific situation. Tax laws vary by jurisdiction and change frequently. Consult a qualified tax professional or CPA for advice tailored to your circumstances.
Inputs
Results
AMT Owed
$0.00
Figures current as of 2024. Source: Internal Revenue Service, Rev. Proc. 2023-34, Section 3.11 (Exemption Amounts for Alternative Minimum Tax, IRC § 55)
How to Use This Calculator
- Enter Total Income including wages, salary, and ordinary income before deductions.
- Select Filing Status to apply the correct AMT exemption amount.
- Enter State & Local Taxes paid — SALT deductions are added back for AMT purposes.
- Set ISO Exercise Spread if you exercised incentive stock options — this is a major AMT preference item.
- Enter Other AMT Preferences (private-activity bond interest, depletion).
- Review AMT Owed — if positive, you pay this in addition to regular tax. Consider timing ISO exercises to minimize AMT.
What each input means
- Total Income ($)
- Your total W-2 wages, salary, and ordinary income before deductions. Regular tax uses current-year federal brackets; AMT exemptions are pinned to 2024 (IRS Rev. Proc. 2023-34) pending an AMT reference-data module.
- Filing Status
- Your federal filing status determines exemption amounts and bracket thresholds.
- State & Local Taxes ($)
- Total state income tax + property tax. The regular tax caps SALT at $10,000; AMT adds back what was deducted.
- ISO Exercise Spread ($)
- Bargain element from exercising incentive stock options (FMV minus exercise price). This is an AMT preference item.
- Other AMT Preferences ($)
- Other AMT adjustments such as private-activity bond interest, depletion, or intangible drilling costs.
What each result means
- AMT Owed
- Additional tax above your regular tax liability due to AMT.
- Total Federal Tax
- Regular tax plus any AMT owed.
- Effective Tax Rate
- Total tax as a percentage of total income.
- AMT Income (AMTI)
- Your income after AMT adjustments and preferences are added back.
- AMT Exemption Used
- Your AMT exemption after phase-out reduction.
- Tentative Minimum Tax
- Tax computed under AMT rules before comparing to regular tax.
- Regular Tax
- Your regular federal income tax liability.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersTotal Income ($) = 250000, Filing Status = 0, State & Local Taxes ($) = 25000, ISO Exercise Spread ($) = 0 = 5 input(s) provided
- Calculate AMT OwedAMT Owed0 = $0
- Calculate Total Federal TaxTotal Federal Tax = regularTax + amtOwed51304 = $51,304
- Calculate Effective Tax Rate20.52 = 20.52%
Figures and sources
- 2024 AMT exemption amounts, phaseout thresholds, and 26%/28% rate breakpoint (2024) — Internal Revenue Service, Rev. Proc. 2023-34, Section 3.11 (Exemption Amounts for Alternative Minimum Tax, IRC § 55)
Engine last updated . Checked against 2 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Why is my AMT Owed showing $0?
At the default inputs ($250,000 income, no ISO exercise, $25,000 SALT), the tentative minimum tax computed under AMT rules doesn't exceed your regular federal tax, so amtOwed = Math.max(0, tentativeMinTax - regularTaxAmount) comes out to zero. AMT typically only bites when a large preference item -- most commonly exercising incentive stock options (the ISO Exercise Spread field) -- pushes AMT Income up sharply relative to regular taxable income.
Are the AMT exemption amounts in this calculator current?
No -- they're pinned to 2024 figures ($85,700 single / $133,300 MFJ exemption, phasing out above $609,350 / $1,218,700 AMTI) per IRS Rev. Proc. 2023-34, flagged in the code as not yet sourced from the site's shared statutory reference-data. Regular Tax, by contrast, does use the current-year federal brackets. Treat the AMT side of this calculator as an estimate pinned to a specific past year, not an auto-updating figure.
Why doesn't raising my State & Local Taxes change my Regular Tax?
This calculator computes regular taxable income using only the standard deduction -- it never itemizes, so State & Local Taxes has zero effect on Regular Tax regardless of the amount. It only enters the calculation through the AMT side, where up to $10,000 of it is added back to AMT Income (since AMT disallows the SALT deduction that regular tax, if it itemized, would have claimed).
Why does Filing Status matter so much for my AMT exemption?
Filing Status selects between two entirely separate 2024 AMT exemption tables -- $85,700 for single filers versus $133,300 for married filing jointly, both phasing out at different AMT Income levels ($609,350 vs. $1,218,700). At incomes below both phase-out thresholds, switching Filing Status is the single biggest driver of AMT Exemption Used, since Total Income and State & Local Taxes don't move the exemption amount itself at all.
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