Finance Calc App

UK Capital gains tax calculator

Short and long-term capital gains tax estimates by region.

By Mitch Duncan Last reviewed Methodology

Your gain

Est. tax owed
£5,280.00
Net gain
£19,720.00
Effective rate
21.1%
£3,000 annual exempt amount applied.

Estimates only

Capital gains tax depends on your full tax picture, allowable losses, deferrals, and local rules not modelled here. Consult a tax professional before filing.

Next step
Income taxAnnual tax — US, UK, CA, AURead the guideHow to Reduce Capital Gains Tax: 9 Legal Strategies
Want the full picture? How to Reduce Capital Gains Tax: 9 Legal Strategies →

How UK Capital Gains Tax is calculated

CGT applies to the profit when you dispose of an asset, after deducting your annual tax-free allowance:

Taxable gain = sale price − cost − costs − annual exempt amount

Unlike the US, the UK has no holding-period distinction — the rate depends on your income and the asset type.

2025/26 rates

Worked example

Sell shares for a £15,000 gain; you're a higher-rate taxpayer.

The gain stacks on top of income to decide whether it falls in the basic or higher band, so part of a gain can be taxed at 18% and part at 24%.

Reliefs and the main home

Your main residence is usually exempt under Private Residence Relief. Business Asset Disposal Relief can cut the rate to 10% on qualifying business sales (up to a lifetime limit). ISAs are entirely outside CGT — gains inside an ISA are never taxed.

Common mistakes

What this doesn't cover

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Income Tax Rates 2025: US, UK, Canada & Australia

Current tax brackets across four countries, side by side.

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Capital Gains Tax Explained

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Key terms

Cost BasisCapital GainsTax-Loss HarvestingCapital Loss Full glossary →

Frequently asked questions

What's the difference between short-term and long-term capital gains?
Short-term gains (assets held one year or less in the US) are taxed as ordinary income at your marginal rate — up to 37%. Long-term gains (held over one year) get preferential rates of 0%, 15%, or 20% depending on income. The UK, Canada, and Australia have different rules — Australia gives a 50% discount on assets held over 12 months, for example.
How is capital gains tax calculated?
Gain = sale price − cost basis − selling expenses. The gain is then taxed at the applicable rate (short- or long-term in the US; ordinary income with a 50% inclusion in Canada; 50% discount in Australia; flat 10/18/20/24% bands in the UK after the annual exempt amount). The calculator above handles each market's rules.
Do I owe capital gains tax on my primary residence?
US: usually no, up to $250,000 of gain ($500,000 married filing jointly) if you've lived there 2 of the last 5 years. UK: principal residence is generally exempt under Private Residence Relief. Canada: principal residence is fully exempt. Australia: main residence is generally exempt with caveats around use and ownership period.
Can I offset capital gains with losses?
Yes — capital losses offset capital gains, and excess losses can offset some ordinary income ($3,000/year in the US; £0 — UK losses carry forward indefinitely against gains; Canada and Australia carry forward losses indefinitely). 'Tax-loss harvesting' — deliberately realising losses to offset gains — is a common end-of-year strategy.

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