Capital Gains Tax UK Calculator
Calculate UK Capital Gains Tax (CGT) on property, shares & other assets. Covers 2023/24 to 2024/25 tax years with accurate HMRC rates and annual exempt amounts.
About
Capital Gains Tax in the UK applies to the profit on disposal of assets exceeding the Annual Exempt Amount (AEA). Miscalculating your liability risks underpayment penalties from HMRC, currently charged at 5.5% of unpaid tax after 30 days plus daily interest at the Bank of England base rate plus 2.5%. The rates diverge sharply by asset class: residential property disposals attract higher rates than shares or other chargeable assets. From 6 April 2024, the AEA dropped to £3,000, down from £6,000 in 2023/24 and £12,300 in prior years. This tool applies the correct rates, band-splitting logic, and exempt amounts for each tax year so you can validate your self-assessment figures before filing.
Note: this calculator assumes a single disposal in a given tax year and does not account for carried-forward losses, Business Asset Disposal Relief (formerly Entrepreneurs' Relief), or Private Residence Relief. If you hold multiple assets disposed in the same year, calculate each separately and manually aggregate. Pro tip: always deduct allowable costs (solicitor fees, stamp duty on acquisition, improvement costs) before computing gain. Omitting these inflates your liability unnecessarily.
Formulas
The core Capital Gains Tax computation follows a three-step pipeline: compute the raw gain, subtract the Annual Exempt Amount, then apply banded rates.
where G = total gain, Psale = disposal proceeds, Pbuy = acquisition cost, C = allowable costs (legal fees, improvement expenditure, stamp duty on purchase).
where TG = taxable gain and AEA = Annual Exempt Amount for the tax year.
Band-splitting applies when the taxpayer has unused basic rate band. Let Rb = remaining basic rate band = Basic Rate Limit − Taxable Income.
where rbasic and rhigher depend on asset type: for residential property in 2024/25, rbasic = 18% and rhigher = 24%. For shares and other assets, rbasic = 10% and rhigher = 20%.
Reference Data
| Tax Year | AEA | Basic Rate (Other) | Higher Rate (Other) | Basic Rate (Residential) | Higher Rate (Residential) | Basic Rate Band Limit |
|---|---|---|---|---|---|---|
| 2024/25 | £3,000 | 10% | 20% | 18% | 24% | £37,700 |
| 2023/24 | £6,000 | 10% | 20% | 18% | 28% | £37,700 |
| 2022/23 | £12,300 | 10% | 20% | 18% | 28% | £37,700 |
| 2021/22 | £12,300 | 10% | 20% | 18% | 28% | £37,700 |
| 2020/21 | £12,300 | 10% | 20% | 18% | 28% | £37,700 |
| 2019/20 | £12,000 | 10% | 20% | 18% | 28% | £37,500 |
| 2018/19 | £11,700 | 10% | 20% | 18% | 28% | £34,500 |
| 2017/18 | £11,300 | 10% | 20% | 18% | 28% | £33,500 |
| 2016/17 | £11,100 | 10% | 20% | 18% | 28% | £32,000 |
| 2015/16 | £11,100 | 18% | 28% | 18% | 28% | £31,785 |