Capital Gains Tax Calculator
Federal and state tax on an investment sale, including NIIT, and what holding to the 12-month mark would save.
Your investment details
Under 12 months is short-term; 12 or more is long-term.
Sets the capital gains rate threshold.
$
≈ $120,000/yr · $10,000/mo · $57.69/hr
Enter the sale details and calculate to see the federal, state and NIIT tax on the gain.
How this is calculated
We estimate the tax on an investment sale by separating short-term gains (taxed like income) from long-term gains (taxed at preferential 0/15/20% rates).
The steps
- Gain = sale price − cost basis.
- Held ≤ 1 year → short-term, taxed at your ordinary income bracket.
- Held > 1 year → long-term, taxed at 0%, 15%, or 20% depending on your taxable income.
- Add any applicable net investment income tax and state tax.
Assumptions
- 2025 federal brackets and long-term rate thresholds.
Good to know
- Simplified — doesn’t model wash sales, carryforwards, or every state nuance.
- A sale at a loss shows $0 tax here; in reality net capital losses can offset other gains and up to $3,000/yr of ordinary income.
Related resources
Assessments
Educational disclaimer. Everything on WealthSerene.com is educational and is not investment advice. Projections and calculations are illustrative; actual results depend on market conditions, your situation and factors outside this tool’s scope. For a decision specific to your situation, consult a qualified financial professional. For tax advice, consult a CPA or Enrolled Agent. View full disclosures