Capital Gains Tax Calculator UK 2026/27

How It Works

Capital gains tax (CGT) is charged on the profit you make when you sell or give away an asset that has gone up in value — shares, a second home, a buy-to-let, crypto or a business. It is the gain that is taxed, not the sale price: gain = sale price − purchase price − allowable costs, where allowable costs include buying and selling expenses such as estate agent and legal fees, and the cost of improvements that add value (for property, an extension counts; redecorating does not). Your main home is normally exempt under Private Residence Relief, and gains inside an ISA or a pension are exempt too.

Three steps turn a gain into a tax bill. Step one: deduct any capital losses, from this year or brought forward — losses reduce your gain before anything else. Step two: deduct the annual exempt amount, the tax-free allowance for capital gains, which is £3,000 per person in 2026/27 (£1,500 for most trustees). You get one £3,000 allowance across all your disposals in a tax year, not £3,000 per sale, and you cannot carry unused allowance forward. Step three: apply the rates to what is left — your taxable gain.

The rates depend on your income, because gains are stacked on top of your taxable income. For 2026/27 the rates for individuals are 18% on the part of the gain that still fits inside your unused basic rate band, and 24% on the rest. The basic rate band is the first £37,700 of taxable income (income above your £12,570 Personal Allowance, which itself tapers above £100,000). So if your taxable income is £32,430, you have £5,270 of basic rate band left, and £5,270 of your taxable gain is charged at 18% while the rest is charged at 24%. If you already pay higher or additional rate income tax, the whole gain is charged at 24%. Since 30 October 2024 the same 18% and 24% rates apply to residential property and to other assets alike — older articles quoting 28% for property are out of date. Capital gains tax is not devolved, so Scottish taxpayers use the same UK basic rate band, not the Scottish bands.

Business Asset Disposal Relief (formerly Entrepreneurs’ Relief) is the exception. Qualifying business disposals — typically selling all or part of a business you have owned for at least two years — are charged at 18% on up to £1 million of lifetime gains, regardless of your income. From 6 April 2026 the relief rate is 18% (it was 14% in 2025/26 and 10% before that). Above the £1 million lifetime limit, the excess is taxed at the normal 18% and 24% rates, with the relief gains filling your basic rate band first.

Worked example (shares): a £20,000 gain on shares, £45,000 of other income, no losses. Taxable income is £45,000 − £12,570 = £32,430, so the unused basic rate band is £5,270. The taxable gain is £20,000 − £3,000 = £17,000. Tax is 18% × £5,270 = £948.60 plus 24% × £11,730 = £2,815.20, giving £3,763.80 — an effective rate of 18.8% on the gain.

Worked example (property): a £60,000 gain on a buy-to-let, with £80,000 of other income. Taxable income is £67,430, above the £37,700 basic rate band, so none of the band is left and the whole taxable gain is charged at 24%. The taxable gain is £60,000 − £3,000 = £57,000, so the tax is 24% × £57,000 = £13,680.00. Because this is UK residential property, the gain must be reported and the tax paid within 60 days of completion.

Worked example (Business Asset Disposal Relief): a £50,000 qualifying business gain. The taxable gain is £50,000 − £3,000 = £47,000, all within the £1 million lifetime limit, so the tax is 18% × £47,000 = £8,460.00, whatever your income.

The table assumes no losses and no Business Asset Disposal Relief. The £30,000 earner has £20,270 of unused basic rate band, so more of each gain is taxed at 18%; the £60,000 earner has none left, so every pound above the allowance is taxed at 24%.

Assumptions

• One individual, one tax year. The calculator is for a UK-resident individual’s disposals in 2026/27. It does not cover trusts, personal representatives, companies (which pay Corporation Tax on gains) or non-UK residents.
• Standard Personal Allowance. The unused basic rate band is worked out using the £12,570 Personal Allowance, tapering above £100,000. Pension contributions and Gift Aid, which can extend the basic rate band, are not modelled.
• Business Asset Disposal Relief assumes you qualify. The calculator applies the 18% rate and the £1 million lifetime limit, but does not check the qualifying conditions (such as the two-year ownership rule).
• Not included: partial Private Residence Relief, lettings relief, hold-over and rollover relief, Investors’ Relief and carried interest.

Sources: GOV.UK — Capital Gains Tax rates and allowances; GOV.UK — Capital Gains Tax: rates; GOV.UK — Capital Gains Tax: allowances; GOV.UK — Capital Gains Tax. Figures checked 13 November 2026.

How to Use This Calculator

Start with your total gain for the tax year — the profit across all your disposals, after deducting purchase costs, allowable expenses and improvements. If you sold more than one asset, add the gains together, because the £3,000 allowance and the rates apply to your total gains for the year, not to each sale separately. Then choose what you sold: shares, crypto and other assets; UK residential property (which triggers the 60-day reporting rule); or a qualifying business asset for Business Asset Disposal Relief.

Next, enter your other income for the year — salary, self-employed profit, pension and rental income, before tax. This is the input most people forget, and it matters: it decides how much of your gain is taxed at 18% and how much at 24%. Finally, enter any capital losses, from this year or brought forward. Results update as you type, and the breakdown shows the split between the 18% and 24% slices, your effective rate and how to report.

Tips and Practical Advice

Use your £3,000 allowance every year. It cannot be carried forward, so a gain you realise just before 5 April uses this year’s allowance, while the same gain in the new tax year would use next year’s. If you are planning to sell a large holding, splitting the sale across two tax years can use two allowances and save up to £720 at the 24% rate.

Time a property sale with the 60-day clock in mind. The deadline runs from completion, not exchange, and the report and payment go through HMRC’s Capital Gains Tax on UK property service — a separate account from Self Assessment. Missing the deadline brings a penalty and interest even if the final bill turns out to be small, so have your figures ready before completion day.

Keep records of every allowable cost. The purchase price, stamp duty, legal fees, estate agent fees and the cost of improvements all reduce your gain, and for a property held for decades those costs can add up to thousands of pounds of tax saved. Without receipts, HMRC can disallow them.

Consider your income year, and remember the wrappers. Because gains stack on top of income, a year with lower earnings leaves more of your basic rate band free, so more of the gain is taxed at 18% instead of 24%. Gains inside an ISA or a pension are free of CGT altogether, and transfers between spouses and civil partners are made on a no-gain, no-loss basis, which lets a couple use two £3,000 allowances and two basic rate bands.

Frequently Asked Questions