About This Calculator
This is a free, independent capital gains tax calculator built to give US investors a clear, instant estimate of their federal and state tax liability — without having to navigate the IRS website or pay for tax software just to see a number.
What the calculator includes
- 2025 federal long-term capital gains rates (0%, 15%, 20%)
- 2025 federal ordinary income rates for short-term gains
- Net Investment Income Tax (NIIT) at 3.8% — applied automatically when applicable
- Capital gains stacking: gains are correctly placed on top of ordinary income to determine bracket
- All 50 states plus Washington D.C. — top marginal rates or flat rates
What it does not include
- Standard deduction or itemized deductions (enter your taxable income, not gross income, for best results)
- AMT (Alternative Minimum Tax)
- State-specific deductions, credits, or exemptions
- Local/city taxes (e.g. New York City surcharge)
- Depreciation recapture on real estate (taxed at up to 25%)
- Installment sales or carried interest rules
Tax rates used
Federal rates are sourced from IRS Rev. Proc. 2024-40 (2025 tax year adjustments). State rates are the top marginal capital gains rate for each state, verified against state revenue department publications and updated for 2025. Most states tax capital gains as ordinary income; Hawaii and Massachusetts are notable exceptions with differentiated holding-period rates.
Disclaimer
This calculator is for educational and informational purposes only. It does not constitute tax, legal, or financial advice. Tax rules are complex, change frequently, and your specific situation may differ materially from the assumptions used here. Always consult a qualified CPA or tax attorney before making investment or tax planning decisions.