Alternative Minimum Tax (AMT) Calculator

2026

Calculate whether you owe AMT from ISO stock options, SALT deductions, or high income.

By Konstantin Iakovlev · Updated September 2026 · Source: IRS — Forms, Instructions & Publications

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Filing Status
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Regular Tax

$40,598.00

Additional AMT

$17,876.00

Total Tax

$58,474.00

AMT Calculation

Regular Taxable Income$200,000.00
+ ISO Exercise Spread$100,000.00
+ SALT Addback (deducted, up to $40,400.00 cap)$15,000.00
Alternative Minimum Taxable Income (AMTI)$315,000.00
AMT Exemption (Single)$90,100.00
AMT Taxable Income$224,900.00
Tentative Minimum Tax$58,474.00

Tax Comparison

Regular Federal Tax$40,598.00
Tentative Minimum Tax (AMT)$58,474.00
Additional AMT Owed$17,876.00
Total Federal Tax$58,474.00
AMT Triggered?Yes

Strategies to Minimize AMT

Spread ISO exercisesExercise over multiple tax years
Time exercises strategicallyExercise when stock price is near strike
AMT credit carryforwardAMT paid on ISOs generates a credit for future years
Consider disqualifying dispositionSelling ISO shares early avoids AMT (but loses LTCG)
Minimize SALT in AMT yearsDefer property tax payments if possible

Use the Alternative Minimum Tax (AMT) Calculator above to calculate your results. Enter your values and see instant results — all calculations run in your browser.

Disclaimer: This calculator is for informational purposes only and does not constitute tax, financial, or legal advice. Results are estimates based on the information you provide and current rates. Always consult a qualified tax professional or financial advisor for advice specific to your situation.

How It Works

The Alternative Minimum Tax (AMT) Calculator determines if you owe additional tax under the parallel AMT system, which ensures high earners pay a minimum amount regardless of deductions. For 2026 the AMT exemption is $90,100 for single filers and $140,200 for married filing jointly, and it phases out at 50 cents per dollar of AMTI above $500,000 and $1,000,000 respectively, running out entirely at $680,200 and $1,280,400.

The calculator computes your Alternative Minimum Taxable Income (AMTI) by adding back certain deductions and preferences to your regular taxable income, then applies AMT rates of 26% and 28%. You owe AMT only if this calculated amount exceeds your regular income tax liability, paying the difference as additional tax.

The classic AMT trigger is a large state and local tax deduction, and it bites in a way people often get backwards. IRC section 56(b)(1)(A)(ii) disallows the SALT deduction for AMT entirely, so whatever you actually deducted on Schedule A comes straight back into AMT income — Form 6251 line 2a simply takes the total from Schedule A line 7. The 2026 cap of $40,400 under IRC section 164(b)(6), which falls by 30% of modified AGI above $505,000 to a floor of $10,000, therefore limits only what you could deduct in the first place; it is not a threshold the addback has to clear. The other reliable trigger is an incentive stock option exercise, because the spread between strike price and fair market value counts as AMT income in the year you exercise even though no regular tax is due on it.

Single Filer with $200,000 Income, a $100,000 ISO Exercise and $15,000 of SALT

  1. 1 Calculate AMTI: start with $200,000 of regular taxable income. The $15,000 SALT deduction is disallowed in full for AMT, so all $15,000 comes back — it sits below the $40,400 cap, which means it was deducted in full on the regular return and therefore returns in full here. The $100,000 ISO exercise spread is an AMT preference item and is added too, giving $315,000 of AMTI.
  2. 2 Apply the AMT exemption: $315,000 is below the $500,000 phase-out threshold for single filers, so the full $90,100 exemption applies. $315,000 - $90,100 = $224,900 of AMT taxable income.
  3. 3 Calculate the tentative minimum tax: $224,900 is below the $244,500 breakpoint where the rate steps from 26% to 28%, so $224,900 x 26% = $58,474.
  4. 4 Compare to regular tax: the 2026 single-filer schedule puts regular tax on $200,000 at $40,598. Because the tentative minimum tax is higher, the extra AMT due is $58,474 - $40,598 = $17,876, for a total federal income tax of $58,474.

Source: IRS — Forms, Instructions & Publications · Last updated: September 2026

Frequently Asked Questions

Who has to pay AMT in 2026?
AMT primarily affects high-income earners who exercise large ISO stock options, claim many preference items, or take a substantial state and local tax deduction. SALT is disallowed outright for AMT under IRC section 56(b)(1)(A)(ii), so the whole amount you deducted comes back into AMT income; the $40,400 cap for 2026 limits what you could deduct, not what returns. The 2026 AMT exemption is $90,100 (single) and $140,200 (married filing jointly), phasing out above $500,000 and $1,000,000 of AMT income.
How is AMT calculated?
Start with taxable income, add back AMT preference items — the ISO exercise spread, and the full state and local tax deduction you claimed on Schedule A — subtract the AMT exemption, and apply the AMT rates: 26% up to $244,500 of AMT taxable income and 28% above it, halved to $122,250 for married filing separately. If the result exceeds your regular tax, you pay the difference.
Do ISO stock options trigger AMT?
Yes, the spread between the exercise price and fair market value of ISOs at exercise is an AMT preference item. A large ISO exercise can trigger tens of thousands in AMT. Consider exercising ISOs gradually across multiple tax years to minimize impact.

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