Calculates Alternative Minimum Tax (AMT) liabilities when exercising Incentive Stock Options (ISOs) before a liquidity event or IPO. For example, exercising 50,000 ISO shares at a $1.00 strike when the Fair Market Value (FMV) is $10.00 creates a $450,000 AMT paper spread, which can trigger an unexpected five-figure AMT tax bill.
Startup Stock Options & AMT Tax Calculator
Estimate cash required to exercise, potential Alternative Minimum Tax (AMT) on paper gains, and net profit at IPO/Exit.
Grant & Grantee Profile
Cash to Exercise
$50,000
Estimated AMT Tax Due
$38,680
Due in Year of Exercise
Net Exit Payout (After Tax)
$846,320
Net Profit at $45/share
Total Upfront Cash Required to Exercise & Hold:
Strike Cost ($50k) + Estimated Tax Liability ($38.6k)
Equity Value Waterfall & Tax Breakdown
Gross Value vs Strike vs Taxes vs NetISO vs NSO Tax Mechanism Breakdown
| Event | Incentive Stock Options (ISO) | Non-Qualified Stock Options (NSO) |
|---|---|---|
| Tax at Grant? | No Tax | No Tax |
| Tax at Exercise? | AMT Spread Trigger (26% - 28%) | Ordinary Income Tax (Up to 37% + FICA) |
| Tax at Sale / Exit? | Long-Term Cap Gains (20%) if held > 1 yr | Cap Gains only on growth above exercise FMV |
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