The AMT is a parallel tax system that makes sure high earners with many deductions pay a minimum tax. Since 2018 far fewer people owe it, but exercising incentive stock options or large state tax deductions can still trigger it.
How to use the AMT Calculator – Alternative Minimum Tax
- Filing status
- Regular taxable income
- State and local taxes deducted (add-back)
- Other AMT adjustments (ISO spread, private bond interest)
- Regular federal income tax (leave 0 to estimate)
Results update as you type, and every field accepts the units shown in its menu.
How it works
Enter your filing status, regular taxable income, regular federal tax, state and local taxes you deducted, and other AMT preference items (such as ISO bargain element).
Tips
- Tax figures here are estimates for planning – your actual tax depends on credits, deductions and local rules.
- Check the tax year and filing status before you rely on a result.
- Use gross (before-tax) figures unless a field asks for take-home pay.
- When in doubt, confirm with the tax authority’s own calculator or a tax professional.
Common mistakes to avoid
- Confusing marginal and effective tax rates.
- Adding sales tax to a price that already includes it.
- Forgetting payroll taxes (Social Security and Medicare) on wages.
Inputs explained
| Field | What to enter |
|---|---|
| Filing status | Choose one: Single, Married filing jointly, Married filing separately, Head of household |
| Regular taxable income | Amount in your currency |
| State and local taxes deducted (add-back) | Amount in your currency |
| Other AMT adjustments (ISO spread, private bond interest) | Amount in your currency |
| Regular federal income tax (leave 0 to estimate) | Amount in your currency |
What each result means
- Alternative minimum taxable income (AMTI) = [Regular taxable income] + [State and local taxes deducted (add-back)] + [Other AMT adjustments (ISO spread, private bond interest)]
- AMT base = max([Alternative minimum taxable income (AMTI)] – [AMT exemption after phase-out], 0)
- Alternative minimum tax owed = max([Tentative minimum tax] – [Regular tax used], 0)
Example values
How the main result changes when Regular taxable income changes and everything else stays at the example values above:
| Regular taxable income | Alternative minimum tax owed |
|---|---|
| 160,000 | 13,176 |
| 240,000 | 11,826 |
| 320,000 | 6,712.75 |
| 400,000 | 1,112.75 |
| 480,000 | 6,712.75 |
| 640,000 | 9,540.75 |
Formula
AMTI = taxable income + state and local taxes deducted + other preference itemsExemption 2026: $90,100 single / $140,200 joint, reduced by 50% of AMTI above $500,000 / $1,000,000Tentative minimum tax = 26% up to $244,500 (+28% above) of AMTI − exemptionAMT = max(TMT − regular tax, 0)Worked example
Inputs — Filing status: Single; Regular taxable income: $320,000; State and local taxes deducted (add-back): $40,000; Other AMT adjustments (ISO spread, private bond interest): $60,000; Regular federal income tax (leave 0 to estimate): $0.
Results — Alternative minimum taxable income (AMTI) = $420,000.00; AMT exemption after phase-out = $90,100.00; AMT base = $329,900.00; Tentative minimum tax = $87,482.00; Regular tax used = $80,769.25; Alternative minimum tax owed = $6,712.75.
Frequently asked questions
Who pays the AMT?
Mostly high earners with large preference items such as incentive stock options.
What are the 2026 AMT exemptions?
$90,100 for single filers and $140,200 for married couples filing jointly.
How is AMT different from regular tax?
It disallows some deductions, then applies 26% and 28% rates.
What formula does the AMT Calculator – Alternative Minimum Tax use?
AMTI = taxable income + state and local taxes deducted + other preference items.