ISO / AMT calculator
How many options can you exercise before AMT hits?
Exercising incentive stock options and holding them doesn't create income — it creates an AMT preference item. There's a precise number of shares you can exercise each year before that costs you anything. This finds it.
Updated for the 2026 rules. The One Big Beautiful Bill Act moved the AMT exemption phaseout down to $500k / $1M and doubled the phaseout rate to 50¢ per dollar — which creates a band where each extra dollar costs 39–42%, not 26–28%. Most calculators still use the old rules.
You can exercise
shares this year with zero AMT
If you exercise all of them instead
What this means
The whole curve
Every row is real — no interpolation.
| Shares | Cash out | Bargain element | AMT owed |
|---|
What this does not include
The numbers used
Check these against the IRS yourself. If they're stale, the answer above is wrong — that's true of every calculator, but most don't show you.
This is a planning tool, not tax advice, and not a substitute for a CPA who can see your whole return. Exercising options is a large, often irreversible financial decision. See our disclaimer.