Business Sale Tax Calculator (QSBS-Aware)

Fast estimate for founders. Simple Mode uses effective federal rates (LT 23.8%, ST 40.8%) and optional state modeling with QSBS conformity.

1) Basic

Portion of the deal you personally receive for stock. Options/wages not modeled here.

2) Shares

Total shares
0
Implied price/share
-

3) QSBS

Must be equal (or more) long-term shares.

4) State Tax (optional)

"Full Conform" mirrors federal inclusion/exclusion %; "No Conform" taxes all LT+ST gains, including QSBS excluded federally. If you live in NY = full conform. If you live in CA = no conform.
Modeled as an extra % on the same base as capital gains (not a separate base).

Your Results

Ready
LT gain (modeled)
$0
ST gain (modeled)
$0
Gross Deal Value$0
Total Federal Tax $0
Total State Tax $0
Total Tax Owed $0
Net Proceeds After Tax $0
Effective Total Tax Rate 0.0%
Federal LT vs ST splitHidden
QSBS excluded amountHidden
QSBS above cap (taxed)Hidden
NIIT componentsHidden
State base & surtax calcHidden
Advanced modeling (QSBS trust stacking, multi-state residencies, 1045 rollovers, deferrals, options, bucket sequencing, charitable vehicles, deal levers, etc.) is shown in client and prospective client sessions.
Assumptions: LT 23.8% (20% + NIIT), ST 40.8% (37% + NIIT). Legacy QSBS (50%/75%) modeled at 28% on included portion + 1.96% AMT add-back on excluded portion. Post-2025 partial tiers (50%/75%) modeled at 28% on included portion; no AMT add-back. 100% exclusion removes regular tax, NIIT, and AMT on the excluded amount. State QSBS treatment per "Conformity". Surtax modeled as added % to same base. Dollar outputs rounded to nearest $10k for display. Planning aid only - not tax advice.
QSBS Basis Disclaimer: For Qualified Small Business Stock (QSBS) purposes, the tax basis used to determine the QSBS exclusion limit may differ from the basis used to calculate taxable capital gain on a sale.In certain situations, including LLC-to-C-corporation conversions, reorganizations, or other restructuring events, a shareholder may have a stepped-up or carryover basis for QSBS exclusion purposes while still recognizing taxable capital gain up to the amount of their economic or historical basis at the time of sale. As a result, even if stock otherwise qualifies for a full QSBS exclusion and the calculator reflects "zero tax", a portion of the sale proceeds may still be subject to capital gains tax. This commonly occurs when a business converts to a C-corporation at a meaningful valuation and is later sold after satisfying the QSBS holding period. This calculator does not model basis mismatches, conversion-related gain, or transaction-specific tax attributes. Actual tax outcomes depend on detailed facts and should be reviewed with qualified tax counsel or a CPA.