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Capital gains tax calculator
Selling shares, funds or a property that is not your main home? See the tax due after the £3,000 allowance, and how much of your gain falls at 18% versus 24%.
Tax year 2026/27. Income means salary, pension and other taxable income before the personal allowance; it decides how much of your gain is taxed at 18% rather than 24%. Your main home is usually exempt.
Capital gains tax due
£3,164
15.8% of your £20,000 gain
- Total gain£20,000
- Tax-free allowance used−£3,000
- £15,270 at 18%£2,749
- £1,730 at 24%£415
- Tax to pay£3,164
Assets held inside an ISA are free of capital gains tax entirely. See the ISA savings calculator.
Common questions
- How much is the capital gains tax allowance in 2026/27?
- £3,000 per person per tax year, the annual exempt amount. It has been £3,000 since April 2024, down from £6,000 the year before and £12,300 before that. Gains up to £3,000 are tax-free; on a £10,000 gain you only pay tax on £7,000. The allowance does not roll over, so an unused allowance is lost at the end of the tax year.
- Are the rates different for property and shares?
- Not any more. Since 30 October 2024 both pay the same two rates: 18% on gains that fit inside your unused basic-rate band and 24% above it. On a £20,000 gain with a £60,000 salary you would pay 24% on £17,000 (after the £3,000 allowance), which is £4,080, whether you sold shares or a buy-to-let flat.
- How do I know whether I pay 18% or 24%?
- Add your taxable gain on top of your taxable income. Whatever fits inside the basic-rate band (£37,700 of income above the £12,570 personal allowance) is taxed at 18%; the rest at 24%. On a £35,000 salary you have £15,270 of basic-rate band left, so the first £15,270 of taxable gain is taxed at 18% and anything above that at 24%.
- When do I have to report and pay capital gains tax?
- Selling UK residential property that is not your main home: within 60 days of completion, using HMRC's online property account, with the tax paid at the same time. For shares and everything else you report through Self Assessment and pay by 31 January after the end of the tax year, so a gain made in May 2026 is due by 31 January 2028.
- Do ISAs escape capital gains tax?
- Yes, completely. Shares and funds held inside a stocks and shares ISA pay no capital gains tax however large the gain, and you do not even report them. You can add up to £20,000 a year. The same gain made in a normal dealing account could lose 24% of everything above £3,000, so where you hold investments matters as much as what you hold.
- Do I pay capital gains tax when I sell my home?
- Usually not. Private residence relief means your main home is exempt for the time you lived in it. The tax mostly applies to second homes, buy-to-lets, inherited property you kept, and investments outside ISAs and pensions. This calculator is guidance, not regulated financial advice.
Future gains are easier to shelter than past ones: the ISA savings calculator shows what a tax-free wrapper is worth over time, and the compound interest calculator shows how reinvested gains snowball.