US Capital Gains Tax Calculator - 2025 Tax Rates
Free calculator to estimate federal and state capital gains taxes with 2025 rates including short-term, long-term, and Net Investment Income Tax
US Capital Gains Tax Calculator 2025
Results
What is a US Capital Gains Tax Calculator?
A US Capital Gains Tax Calculator is a comprehensive financial tool that calculates the federal and state taxes owed on profits from selling investments like stocks, bonds, real estate, or cryptocurrency. It applies 2025 IRS tax rates for both short-term capital gains (taxed as ordinary income) and long-term capital gains (preferential rates of 0%, 15%, or 20%), plus the 3.8% Net Investment Income Tax for high earners.
This calculator is essential for:
- Investment planning - Estimate tax liability before selling assets
- Tax optimization - Compare short-term vs long-term holding strategies
- Portfolio rebalancing - Calculate after-tax proceeds for investment decisions
- Tax loss harvesting - Identify opportunities to offset gains with losses
- Retirement planning - Project tax impact of liquidating investments
For calculating your overall federal income tax including capital gains, use our Federal Income Tax Calculator to determine your complete tax liability across all income sources.
To understand capital gains tax in the UK, explore our UK CGT Calculator for comprehensive calculations with UK tax rates and allowances.
For cryptocurrency-specific capital gains calculations, check our US Crypto Tax Calculator to track gains and losses across multiple transactions.
To calculate dividend taxes on investment income, try our Dividend Tax Calculator for qualified and ordinary dividend tax rates.
How US Capital Gains Tax Calculator Works
The calculation follows IRS guidelines for capital gains taxation (2025):
Short-Term Capital Gains (held < 1 year)
Tax = Gain × Ordinary Income Tax Rate (10%-37%)
Taxed at your regular income tax bracket based on total taxable income
Long-Term Capital Gains (held >= 1 year)
0%: Single ≤ $48,350, MFJ ≤ $96,700
15%: Single $48,351-$533,400, MFJ $96,701-$600,050
20%: Single > $533,400, MFJ > $600,050
Net Investment Income Tax (NIIT)
Additional 3.8% if MAGI > $200K (single) or $250K (MFJ)
NIIT = Lesser of (Net Investment Income or Excess MAGI) × 3.8%
Total Tax
Total = Federal Tax + NIIT + State Tax
Net Proceeds = Gain - Total Tax
The calculator automatically determines which tax rate applies based on your income level, filing status, and holding period, then adds applicable NIIT and state taxes.
Key Concepts Explained
Capital Asset
Property held for investment or personal use including stocks, bonds, mutual funds, real estate, cryptocurrency, collectibles, and business assets. Sales generate capital gains or losses that must be reported to the IRS.
Holding Period
The length of time you own an asset before selling. Assets held less than one year generate short-term gains taxed as ordinary income (10%-37%). Assets held one year or more qualify for preferential long-term rates (0%, 15%, or 20%).
Cost Basis
The original purchase price plus improvements, commissions, and fees. Capital gain equals sale price minus cost basis. Accurate basis tracking is essential for correct tax calculation and can include adjustments for splits, dividends, or inheritance.
Tax Loss Harvesting
Strategy of selling investments at a loss to offset capital gains and reduce tax liability. Losses offset gains dollar-for-dollar, with up to $3,000 excess losses deductible against ordinary income annually. Remaining losses carry forward indefinitely.
How to Use This Calculator
- Enter capital gain or loss amount - Input the profit (positive) or loss (negative) from selling your investment. Calculate as sale price minus cost basis.
- Select holding period - Choose Short-Term (held less than 1 year) or Long-Term (held 1 year or more) to determine applicable tax rates
- Select filing status - Choose Single, Married Filing Jointly, Married Filing Separately, or Head of Household for accurate bracket application
- Enter taxable income - Input your taxable income excluding the capital gain to properly position you in the correct tax brackets
- Enter state tax rate - Input your state's income tax rate (use 0 for states with no income tax like Texas or Florida)
- Click Calculate - View total tax owed, federal tax, NIIT, state tax, and net proceeds after taxes instantly
- Review the breakdown - Analyze all tax components including applicable tax rates and effective rate on your capital gain
Benefits of Using This Calculator
- Accurate 2025 tax rates - Calculate using current IRS long-term capital gains brackets and NIIT thresholds for precise tax estimates
- Holding period optimization - Compare short-term vs long-term tax implications to determine optimal selling timing and save thousands
- NIIT awareness - Automatically calculates 3.8% Net Investment Income Tax for high earners exceeding income thresholds
- State tax integration - Include state income tax for complete after-tax proceeds calculation across all jurisdictions
- Investment decision support - Make informed buy/sell decisions by understanding true after-tax returns on investments
- Tax planning insights - Identify opportunities for tax loss harvesting, bracket management, and strategic asset liquidation timing
Factors That Affect Your Results
- Holding period timing - Holding assets just 12 months vs 11 months can reduce tax rates from 37% to 20%, saving 17% on high-income sales
- Income bracket positioning - Long-term capital gains can push you across 0%, 15%, or 20% thresholds, with portion of gains taxed at each applicable rate
- NIIT threshold crossings - Modified AGI exceeding $200K (single) or $250K (MFJ) triggers additional 3.8% tax on investment income
- State tax variations - State rates range from 0% (no income tax states) to over 13% (California), dramatically affecting net proceeds
- Capital loss carryforwards - Prior year losses offset current gains, reducing taxable amount and potentially eliminating tax liability entirely
- Asset type differences - Collectibles taxed at maximum 28%, qualified small business stock may exclude 50-100%, Section 1250 property has 25% unrecaptured depreciation
Frequently Asked Questions
What is the difference between short-term and long-term capital gains?
Short-term capital gains apply to assets held for less than one year and are taxed as ordinary income at your regular tax bracket (10%-37%). Long-term capital gains apply to assets held for one year or more and receive preferential tax rates of 0%, 15%, or 20% depending on your income level.
What is the Net Investment Income Tax (NIIT)?
The NIIT is an additional 3.8% tax on investment income including capital gains for high earners. It applies when your modified adjusted gross income exceeds $200,000 (single) or $250,000 (married filing jointly). This tax is assessed on the lesser of your net investment income or the amount by which your MAGI exceeds the threshold.
How are capital losses treated for tax purposes?
Capital losses can offset capital gains dollar-for-dollar. If your losses exceed your gains, you can deduct up to $3,000 ($1,500 married filing separately) of excess losses against ordinary income per year. Remaining losses can be carried forward indefinitely to future tax years.
Do I qualify for the 0% long-term capital gains rate?
For 2025, you qualify for the 0% long-term capital gains rate if your taxable income (including the capital gain) is $48,350 or less for single filers, or $96,700 or less for married filing jointly. This makes it possible to realize significant capital gains without owing any federal tax.
How do state taxes affect capital gains?
Most states tax capital gains as ordinary income at their standard income tax rates, though some states like California, New York, and New Jersey have rates exceeding 10%. Nine states (Alaska, Florida, Nevada, New Hampshire, South Dakota, Tennessee, Texas, Washington, Wyoming) have no state income tax on capital gains.
Are there strategies to minimize capital gains tax?
Yes, several strategies exist: hold assets over one year for preferential long-term rates, harvest tax losses to offset gains, time sales to stay in lower tax brackets, donate appreciated assets to charity, use 1031 exchanges for real estate, contribute to opportunity zones, or hold until death for stepped-up basis.