Capital gains tax calculator 2026/27
- CGT on shares, funds and property
- £3,000 annual exempt amount applied
- 18% and 24% rates, split by your income
- Shows the exact basic and higher-rate portions
Capital gains tax to pay
£3,060
On a £20,000 gain after the £3,000 allowance.
| Total gain | £20,000 |
| Less annual exempt amount | −£3,000 |
| Taxable gain | £17,000 |
| Tax on portion at 18% | £3,060 |
| Tax on portion at 24% | £0 |
| Capital gains tax | £3,060 |
Enter your taxable income (income after your personal allowance and reliefs). The gain stacks on top of it to decide how much is taxed at 18% versus 24%. Figures use HMRC 2026/27 rates. Source: gov.uk
Capital gains tax is charged on the profit when you sell an asset that's gone up in value: shares, funds, a second property, a business. You're taxed on the gain, not the sale price. Buy shares for £10,000, sell for £30,000, and the £20,000 gain is what matters.
Everyone gets a £3,000 tax-free allowance each year, the annual exempt amount. Only gains above that are taxed. The rate depends on your income: the part of the gain that fits within your remaining basic-rate band is taxed at 18%, and anything above at 24%, for the 2026/27 tax year.
| Step | Amount |
|---|---|
| Total gain | £20,000 |
| Less annual exempt amount | £3,000 |
| Taxable gain | £17,000 |
| Already a higher-rate taxpayer, so all at 24% | £17,000 × 24% |
| Capital gains tax | £4,080 |
A basic-rate taxpayer with the same gain would pay less, because part of the gain would fall in the 18% band. That's why the calculator asks for your income: it decides how much of your gain gets the lower rate.
Selling your main home is normally free of CGT thanks to Private Residence Relief. The tax bites on second homes, buy-to-let properties, and gains on shares held outside an ISA or pension. Anything inside an ISA or pension is free of CGT entirely, which is the main reason to use those wrappers.
The £3,000 allowance can't be carried forward, so if you have a large gain it can pay to split the disposal across two tax years, using £3,000 in each. Transfers between spouses are also free of CGT, so a couple can use both allowances and both sets of basic-rate bands. For the income side of your finances, the main salary calculator shows where your basic-rate band runs out.