Startup Equity tools
How much could you save by filing an 83(b)?
Enter your grant details to see the estimated difference in tax exposure between filing and not filing.
Exercise or purchase price
$
Current fair market value per share
$
Projected FMV per share at exit
$
Federal ordinary income rate
%
Federal LTCG rate (typically 15–20%)
%
Estimated tax savings from filing 83(b)
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Enter your details above to calculate
With 83(b) filed
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Tax at grant + LTCG at exit
Without 83(b)
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Ordinary income tax at each vest
Without 83(b) — taxable events at each vest
| Year | FMV per share | Shares vested | Ordinary income | Tax owed |
|---|
ISO holders: If you hold ISOs and are early exercising, the spread at exercise may also trigger Alternative Minimum Tax (AMT). This calculator does not account for AMT. Speak with a CPA before exercising.
This calculator is illustrative only and is not tax advice. It assumes equal annual vesting tranches and linear appreciation from grant FMV to exit FMV. It does not account for state taxes, AMT, the 1-year cliff, or post-vesting appreciation. Your actual tax liability will depend on your company's 409A history, grant terms, option type (ISO vs NSO), and personal tax situation. Consult a qualified CPA or tax attorney for advice specific to your circumstances.
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