Capital Gains Tax Calculator

What Is a Capital Gains Tax Calculator?

A Capital Gains Tax Calculator helps you estimate the tax that may be payable when you dispose of an asset for more than it cost you. Capital Gains Tax, commonly abbreviated to CGT, can apply to gains from assets such as shares, investment property, valuable personal possessions and certain business assets.

This free UK Capital Gains Tax Calculator is designed for the 2026/27 tax year, which runs from 6 April 2026 to 5 April 2027. It estimates your taxable gain after eligible losses and the £3,000 annual exempt amount, then applies the relevant 18% and 24% individual CGT rates according to your taxable income.

Why Use Capital Gains Tax Calculator?

Capital Gains Tax can be difficult to estimate because the rate applied to your gain depends partly on your taxable income. This calculator brings the main elements together so you can quickly estimate your potential CGT liability.

How to Use the Capital Gains Tax Calculator

Enter the details of your capital gain and income, then calculate your estimated Capital Gains Tax for the 2026/27 tax year.

1. Enter your capital gain — Enter the profit made on the disposal before deducting eligible losses and the annual exempt amount.
2. Enter allowable losses — Add any eligible capital losses that can be used against your gains.
3. Enter your taxable income — Enter your annual taxable income after your Personal Allowance and applicable Income Tax reliefs.
4. Calculate your CGT — Select Calculate Tax to apply the £3,000 annual exempt amount and the 18% and 24% CGT rates.

UK Capital Gains Tax Rates for 2026/27

For the 2026/27 tax year, most individuals have a Capital Gains Tax annual exempt amount of £3,000. This means you generally only pay CGT on overall gains above £3,000 after eligible losses and applicable reliefs have been taken into account.

For individuals, the main Capital Gains Tax rates for gains made from 6 April 2026 are 18% for gains falling within the unused basic rate band and 24% for gains above the basic rate band. The same 18% and 24% rates apply to residential property gains under the standard rules.

How Your Income Affects Capital Gains Tax

Your taxable income affects the amount of the basic Income Tax band that remains available for your capital gain. For 2026/27, the basic rate band is £37,700 after allowances. If your taxable income is below £37,700, some of your taxable gain may fit within the unused portion of that band and be charged at 18%. Any remaining taxable gain above the available basic rate band is generally charged at 24%.

Calculating Your Taxable Capital Gain

A capital gain is generally calculated by comparing the amount received for an asset with its acquisition cost and relevant allowable costs. Once your gains and losses for the tax year have been established, eligible losses can reduce the overall gains. The annual exempt amount is then deducted from the remaining gains to determine the amount subject to CGT.

For example, if you have a £30,000 gain and no allowable losses, the £3,000 annual exempt amount would leave £27,000 of taxable gains before considering the available Income Tax basic rate band. If you had £20,000 of taxable income, £17,700 of the gain could potentially fall within the remaining basic rate band and the remainder would normally be taxed at 24%.

Capital Gains Tax Allowances, Losses and Reliefs

The £3,000 annual exempt amount applies to individuals for the 2026/27 tax year. It is not an allowance against each individual disposal; instead, it generally applies to your overall gains for the tax year after relevant losses and reliefs have been considered.

Some assets and transactions can benefit from specific exemptions or reliefs. Your main home may qualify for Private Residence Relief, while qualifying business disposals may potentially qualify for Business Asset Disposal Relief. Certain gifts, reorganisations and other transactions can also have special Capital Gains Tax treatment.

This calculator deliberately focuses on the standard individual CGT calculation and does not attempt to determine eligibility for specialist reliefs. It should therefore be used as a planning estimate rather than as a substitute for a Self Assessment calculation or professional tax advice.

The calculator also assumes that the taxable income figure you enter already reflects your Personal Allowance and applicable Income Tax reliefs. It does not calculate Income Tax itself. For the 2026/27 tax year, the standard basic rate band is £37,700 after allowances.

Frequently Asked Questions