Tax calculator
ISO Exercise and AMT Calculator
Could exercising and holding incentive stock options create extra federal tax?
What this tool helps you answer
Could exercising and holding incentive stock options create extra federal tax?
Exercising incentive stock options can create alternative minimum tax before the shares are sold. This calculator derives the bargain element from the shares, exercise price, and exercise-date value, then applies the 2026 AMT exemption and rates without pretending that special capital-gain math or a same-year sale can be solved from incomplete facts.
Transparent method
How the estimate works
See how the estimate is calculated
Multiply exercised shares by the positive difference between exercise-date value and strike price, unless all shares were marked sold during the same tax year.
Add that ISO adjustment and other entered AMT changes to taxable income, then apply the 2026 filing-status exemption, phaseout, and 26% and 28% rates.
Compare tentative minimum tax with entered regular tax, but withhold a dollar result when qualified dividends or long-term gains require the special Form 6251 worksheet.
What to check before acting on the result
How to read it
- Confirm the exercise-date fair market value and shares on Form 3921.
- Treat a same-year sale as a separate tax calculation rather than assuming the holding adjustment applies.
- Compare the tax cash need with the risk of holding the stock before deciding how many options to exercise.
Not included
- The special AMT capital-gain worksheet when qualified dividends or long-term gains are present
- A same-year disqualifying-sale regular-tax calculation
- Prior-year minimum tax credit or Form 8801
- State tax, payroll reporting, estimated-tax penalties, or advice to exercise, hold, or sell
Common questions
Frequently asked questions
What is the ISO bargain element?
It is generally the exercise-date fair market value minus the strike price, multiplied by shares exercised. Shares held after the year of exercise can create an AMT adjustment.
Does selling ISO shares in the same year avoid AMT?
A same-year disposition generally changes the AMT adjustment, but it also creates regular-tax consequences. The actual sale and payroll records must be reconciled.
Why does the tool ask for regular tax?
AMT is generally the amount by which tentative minimum tax exceeds regular tax, so regular tax is necessary for the comparison.
Can AMT be recovered later?
Some AMT from timing items may create a future minimum-tax credit. That separate Form 8801 calculation is not included here.
Sources
Rules and references behind this calculator
Want the fine print? See sources, methods, and limits.