Capital Gains Tax Calculator
Capital gains tax calculator for US and UK — estimate CGT on shares, property, and other assets with long-term and short-term rates.
Last checked 2 July 2026 How we calculate this →
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Inputs
Original price you paid for the asset
Price you sold (or plan to sell) the asset for
Your ordinary taxable income (excl. the capital gain)
Capital Gains Tax
$4,500
on a $30,000 gain (15.0% effective rate)
Capital Gain
$30,000
Effective Rate
15.00%
You Keep
$25,500
Tax Breakdown
| Capital Gain | $30,000 |
| Federal Tax (long-term rates) | $4,500 |
| Total Tax | $4,500 |
Short-Term vs Long-Term Tax
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How it works
What Is Capital Gains Tax?
Capital gains tax is a tax on the profit from selling an asset for more than you paid. It applies to stocks, bonds, mutual funds, real estate (other than your main home in most cases), cryptocurrency, and other investments.
The key question in both the US and UK is: how much of your gain do you actually keep after tax?
2026 update: UK rates remain 18%/24% (unified since October 2024), with the annual exempt amount still just £3,000. In the US, long-term capital gains brackets were adjusted for inflation.
US Capital Gains Tax (2026)
Long-Term vs Short-Term
The US distinguishes sharply between:
- Long-term gains (held over 1 year): taxed at preferential rates of 0%, 15%, or 20%
- Short-term gains (held 1 year or less): taxed at ordinary income rates (10%–37%)
This is the single biggest factor in your tax bill. Holding an extra month can save thousands.
Long-Term Capital Gains Brackets (2026)
| Taxable Income (Single) | Rate |
|---|---|
| Up to $49,450 | 0% |
| $49,451 – $545,500 | 15% |
| Over $545,500 | 20% |
Net Investment Income Tax (NIIT)
High earners also face an additional 3.8% NIIT on investment income when modified AGI exceeds $200,000 (single) or $250,000 (married). This effectively creates a top rate of 23.8% on long-term capital gains.
UK Capital Gains Tax (2026/27)
Rates (From 30 October 2024)
The rates were simplified and increased:
- Basic rate taxpayers: 18% on all gains
- Higher/additional rate taxpayers: 24% on all gains
The rate depends on your total taxable income plus gains — if gains push you into the higher rate band, part is taxed at 18% and the rest at 24%.
Annual Exempt Amount
The first £3,000 of gains each tax year is tax-free. This was cut from £12,300 just two years ago — a dramatic reduction that means even modest gains now trigger a tax bill.
Strategies to Reduce Capital Gains Tax
- Hold for over a year (US): The difference between short-term and long-term rates can halve your tax bill
- Use ISAs (UK): Gains within an ISA wrapper are completely tax-free — no annual limit on growth
- Tax-loss harvesting: Sell losing investments to offset gains in the same tax year
- Use your annual exempt amount (UK): Realise up to £3,000 in gains each year tax-free
- Primary residence exemption: Both countries offer significant relief on your main home
When to Use This Calculator
- Before selling investments to estimate your tax bill
- Comparing short-term vs long-term holding strategies (US)
- Planning end-of-year tax-loss harvesting
- Deciding between taxable accounts and tax-sheltered wrappers (ISAs, 401(k)s)
Real-World Examples
US: Selling $50,000 of stock held for 2 years
A single filer with $75,000 taxable income selling stock for a $30,000 long-term gain owes $4,500 in federal capital gains tax (15% rate) with no NIIT. The 15% rate applies because their total income ($105,000) exceeds the 0% threshold but stays below the 20% threshold. Had they sold within a year, the same gain would be taxed at 22% ($6,600) — holding longer saved $2,100.
UK: Selling a buy-to-let for £50,000 profit
A higher-rate UK taxpayer selling a buy-to-let property with a £50,000 gain pays £11,280 in CGT: the first £3,000 is covered by the annual exempt amount, and the remaining £47,000 is taxed at 24%. The effective rate on the total gain is 22.56%. Using an ISA wrapper for investments would shelter gains entirely — worth considering for future investments.
US: High-income investor selling with NIIT
A single filer earning $250,000 who sells assets for a $200,000 long-term gain faces $30,000 in federal CGT (the gain stacks on top of income and falls entirely in the 15% bracket, which runs to $545,500) plus $7,600 in NIIT (3.8% on the full gain, since income exceeds the $200,000 NIIT threshold). Total tax: $37,600, effective rate 18.8%. Tax-loss harvesting — selling losing positions to offset gains — could reduce this bill.
Frequently Asked Questions
What is capital gains tax?
What is the difference between short-term and long-term capital gains in the US?
What is the UK Capital Gains Tax annual exempt amount?
Do I pay capital gains tax on my main home?
What is the Net Investment Income Tax (NIIT)?
What are the UK CGT rates from October 2024?
Sources & Methodology
Data Sources
- IRS — Capital Gains and Losses
- IRS — Net Investment Income Tax
- GOV.UK — Capital Gains Tax rates
- GOV.UK — Capital Gains Tax annual exempt amount
Last verified: 2 July 2026
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