Calculate capital gains tax on investment sales. Handles short-term (ordinary income) and long-term (0%/15%/20%) rates plus NIIT for high earners.
How to Use This Capital Gains Tax Calculator
Enter your purchase price (cost basis including commissions), your sale price, and select whether the asset was held short-term (1 year or less) or long-term (more than 1 year). Enter your ordinary income to determine which capital gains bracket applies.
Long-term gains benefit from preferential 0%, 15%, or 20% rates depending on your total taxable income. Short-term gains are added to your ordinary income and taxed at your marginal rate.
The Formula
Capital Gain = Sale Price β Purchase Price (Cost Basis)
Short-Term: Gain taxed at ordinary income marginal rate
Long-Term Rate: 0% / 15% / 20% based on total taxable income
NIIT: 3.8% if MAGI > $200K (single) / $250K (married joint)
Net Proceeds = Sale Price β Capital Gains Tax
Example
Chris, single, bought stock for $50,000, sold for $80,000 after 2 years, $75K other income:
Capital gain: $30,000 (long-term)
Total taxable income: $75,000 β $15,000 (std) + $30,000 = $90,000
LTCG rate: 15% (income between $48,350 and $533,400)
CG tax: $30,000 Γ 15% = $4,500
Net proceeds: $80,000 β $4,500 = $75,500
Frequently Asked Questions
What is the difference between short-term and long-term capital gains?
Short-term capital gains apply to assets held for one year or less and are taxed as ordinary income at your regular marginal rate (10%β37%). Long-term capital gains apply to assets held for more than one year and are taxed at preferential rates of 0%, 15%, or 20% depending on your taxable income and filing status.
What are the 2025 long-term capital gains tax rates?
For 2025, the 0% rate applies to single filers with taxable income up to $48,350; 15% applies from $48,350 to $533,400; 20% applies above $533,400. For married filing jointly: 0% up to $96,700; 15% up to $600,050; 20% above. These thresholds are based on total taxable income, including the gains.
What is the Net Investment Income Tax (NIIT)?
The NIIT is an additional 3.8% tax on the lesser of your net investment income OR the amount by which your modified AGI exceeds $200,000 (single) / $250,000 (married filing jointly). Investment income includes capital gains, dividends, interest, and rental income. The NIIT is on top of the regular capital gains rate.
How do I calculate my capital gain?
Capital gain = Sale Price β Adjusted Cost Basis. Your adjusted cost basis is the original purchase price plus any improvements, commissions, and fees paid at purchase, minus any depreciation claimed. For stocks, it is typically the purchase price plus brokerage commissions. Your broker reports this on Form 1099-B.
Can I offset capital gains with capital losses?
Yes. Capital losses offset capital gains dollar-for-dollar. If losses exceed gains, you can deduct up to $3,000 of the excess against ordinary income per year. Remaining losses carry forward to future years indefinitely. Short-term losses first offset short-term gains, then long-term gains; long-term losses work similarly.