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

Your Personal Sale Proceeds (stock)

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

Cost Basis (total)

2) Shares

Long-term shares (equal or more than 1 year)

Short-term shares (< 1 year)

Total shares

Implied price/share

3) QSBS

QSBS-eligible shares

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

QSBS-eligible portion

Date stock acquired Required if QSBS > 0

Sale date

4) State Tax (optional)

Include state tax?

QSBS conformity

"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.

State capital gains tax rate (%)

State surtax (%)

Modeled as an extra % on the same base as capital gains (not a separate base).

Your Results

Ready

LT gain (modeled)

ST gain (modeled)

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.