LightUp Tax equity tax tools
U.S. stock and equity tax calculators
Use 2026 federal tax parameters to estimate RSU withholding gaps, ISO AMT, NSO exercise tax, ESPP sale tax, and capital gains.
Calculation methodology reviewed by Carina Luo, CPA
Based on 2026 federal tax rules. Last reviewed July 2026.
The short answer
Equity tax is not one tax-rate question. Timing, award type, basis, holding period, withholding, and full-year income interact. These calculators turn one risk at a time into a clear estimate; large positions, multiple lots, multi-state sourcing, and historic AMT credits require a full projection.
RSU withholding gap
Estimate W-2 income, payroll taxes, federal and state tax, cost basis, and the cash shortfall that sell-to-cover may leave behind.
Open calculatorISO and AMT
Estimate the ISO bargain element, exercise cash, regular and AMT basis, incremental AMT, and an approximate no-new-AMT share limit.
Open calculatorNSO exercise tax
Estimate compensation income, payroll tax, withholding, cash exercise cost, adjusted stock basis, and later capital gain.
Open calculatorESPP sale tax
Compare qualifying and disqualifying dispositions, ordinary income, adjusted basis, capital gain, and after-tax profit.
Open calculatorCapital gains
Estimate short- or long-term federal tax, NIIT, state tax, after-tax gain, and net sale proceeds.
Open calculatorNeed a full projection?
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Calculated in your browser
Inputs stay in your browser for calculation. Contact details and a summary are saved only if you submit them.
Uses 2026 parameters
Includes 2026 ordinary brackets, capital-gain thresholds, AMT parameters, and the Social Security wage base.
Shows basis and tax character
Shows wages, capital gain, payroll tax, NIIT, and regular/AMT basis rather than one unexplained tax number.