SKstackkit
← all tools
Equity

Secondary Sale Tax

Tax on selling vested ISO / NSO / RSU shares.

Heads up — Estimate only — not tax advice. Tax rules change; verify with a CPA before filing or making decisions.
Net after taxes
$136,610
Total tax
$53,390
28.1% of gain
Ordinary income
$0
Capital gain
$190,000
Federal — ordinary
$0
marginal 24%
Federal — capital
$28,500
0/15/20% stacked
NIIT (3.8%)
$7,220
State
$17,670
CA
AI explainer

Ask anything about your result

The math above is deterministic. AI explains what it means — it never recalculates the numbers.

About

Estimate tax on selling vested ISO, NSO, or RSU shares — including the ordinary-vs-capital split, NIIT, and state tax. Designed for tender offers and post-IPO sales.

How it works

  1. 01Pick grant type: ISO, NSO, or RSU.
  2. 02Enter shares, strike, FMV at exercise/vest, and sale price.
  3. 03ISO (qualifying): all gain is long-term capital. NSO: spread at exercise is ordinary, post-exercise gain is capital. RSU: FMV at vest is ordinary, post-vest gain is capital.
  4. 04We apply 37% federal ordinary, 20% federal LTCG, 3.8% NIIT, and your state rate.

Examples

ISO held > 1 yr after exercise

10,000 ISO at $1 strike, exercised at $10 FMV, sold at $20 long-term. Full $190k gain is LTCG. At CA rates, net is roughly $130k–$145k.

RSU sold same day as vest

1,000 RSU vesting at $100 = $100k ordinary income. No capital gain. Federal+state often takes 40–50%.

FAQ

Does this calculate AMT?+
No — AMT on ISO exercise (the spread) is a separate calculation. Be cautious exercising large ISO blocks while still private.
What about QSBS exclusion?+
Use the QSBS Eligibility Checker. If qualified, up to $10M of gain can be 100% federal-tax-free.
Why 37% ordinary?+
We use the top federal bracket as a conservative estimate. Your actual rate may be lower — but with large ISO/RSU events, you're usually in the top bracket.

Related tools

Equity
QSBS Eligibility Checker
Section 1202 — are your gains tax-free up to $10M?
Compensation
Equity Vesting Schedule
4-year, 1-year cliff. See what's vested today.
Compensation
Equity Offer Evaluator
% ownership × likely outcomes → expected $ value.
Compensation
Salary & Tax Calculator
Gross → net take-home across US federal + state brackets.