QSBS Tax Savings Calculator — Section 1202 Exclusion Estimator

Estimate your Section 1202 exclusion

This estimates federal tax on one issuer’s qualifying stock acquired after September 27, 2010. It does not determine QSBS eligibility. Enter the acquisition date after applicable holding-period tacking. State taxes, AMT, loss netting, installment sales, and multiple acquisition tranches are not modeled.

Acquisition date after tacking Sale date Realized qualifying gain ($) Basis for the 10× limit ($)

Use qualifying basis in this issuer’s QSBS disposed of in the taxable year, disregarding basis additions after original issuance and applying any special basis rules.

Remaining per-issuer dollar limit ($)

Use the remaining dollar limit after prior use and old/new-stock coordination. The starting amount is $10 million for acquisitions through July 4, 2025 or $15 million for later acquisitions. The newer amount is indexed after 2026: enter the applicable adjusted amount yourself. This tool does not forecast indexing or automatically subtract prior use. Married filing separately has reduced dollar limits; review joint-filer and trust treatment separately.

Assumed federal rate on ordinary long-term gain (%) Assumed rate on the nonexcluded part of eligible gain (%) Assume 3.8% NIIT applies to all taxable gain

The 20% and 28% inputs are illustrative maximum rates, not rates that apply to every taxpayer. NIIT depends on income and other facts. Use your advisor’s assumptions.

Calculate federal estimate

For the qualification rules, see the QSBS eligibility checklist and Section 1202. This is an educational estimate, not a tax-return calculation.

Washington update (effective 2028)

Washington’s enacted 2028 income tax starts with federal AGI, applies state allocation and modifications, and then applicable deductions and credits. Section 302 separately removes net long-term capital gain or loss and, for taxpayers owing Washington capital gains tax, adds the Washington taxable capital gains plus the capital gains standard deduction. The income-tax standard deduction is shared by spouses and registered domestic partners and is prorated for people who are not residents for the full year. See the Washington income-tax overview and capital gains statute.

Gain actually excluded under Section 1202 generally stays outside Washington’s capital gains tax and its enacted 2028 income tax. A partial exclusion or gain above the available limit can leave taxable gain. This calculator estimates federal tax only; it does not calculate Washington or other state tax.

If the numbers here matter to a real transaction, the next step is confirming your stock actually qualifies. Start with a QSBS Issue-Spotting Review, or book a 20-minute call.