UK Capital Gains Tax Calculator
Estimate the UK Capital Gains Tax owed on the disposal of assets such as shares or property, applying the 2024/25 annual exempt amount and the correct CGT rates.
How to use this tool
- Enter total capital gain, annual exempt amount, asset type and income tax band in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your capital gains tax due and the full breakdown beneath it.
⚠ This tool provides general estimates for education only and is not financial, tax or legal advice. Figures may not reflect your situation — verify with a qualified professional.
Formula
Taxable Gain = Total Gain − Annual Exempt Amount
CGT = Taxable Gain × CGT Rate
2024/25 rates — Shares: Basic 10%, Higher 20%; Residential Property: Basic 18%, Higher 24%.
How it works
UK Capital Gains Tax (CGT) is charged on gains made when you dispose of a chargeable asset. For 2024/25, each individual has an Annual Exempt Amount of £3,000. Gains above this threshold are taxed at rates that depend on the asset type and the taxpayer's income tax band.
This calculator applies a single flat rate to the entire taxable gain. In practice, if your taxable gain spans the basic-rate band limit, a blended rate may apply. This calculator does not account for losses brought forward, business asset disposal relief (BADR), or the interaction with total income. Consult HMRC guidance or a tax adviser for a precise calculation.
Worked example
Higher-rate taxpayer sells shares with a £20,000 gain
- Total capital gain = £20,000
- Annual Exempt Amount 2024/25 = £3,000
- Taxable gain = £20,000 − £3,000 = £17,000
- CGT rate (higher rate, shares) = 20%
- CGT = £17,000 × 20% = £3,400
Capital Gains Tax due = £3,400; net gain after tax = £16,600.
Common mistakes to avoid
- Forgetting to deduct allowable costs (purchase costs, improvement costs, selling fees) before calculating the gain, overstating the taxable amount.
- Using the wrong CGT rate — residential property disposals use 18%/24% rates, while shares use 10%/20% rates; mixing them up materially misstates the liability.
- Overlooking the annual exempt amount (GBP 3,000 for 2024/25), which reduces the taxable gain before applying the rate.
Key terms
- Annual Exempt Amount (AEA)
- The amount of capital gains you can make in a tax year before CGT is charged; £3,000 for 2024/25.
- Disposal
- Any event that triggers a CGT calculation, including a sale, gift, transfer, or exchange of an asset.
- Basic rate band
- The income tax band (up to £50,270 total income for 2024/25) at which the lower CGT rates apply.
- Business Asset Disposal Relief (BADR)
- A relief that reduces the CGT rate to 10% on qualifying business asset disposals, subject to a lifetime limit.
Frequently asked questions
- How do I know whether to use the basic-rate or higher-rate CGT band?
- Add your taxable capital gain to your total income for the year. The portion that falls within the basic-rate income tax band (up to GBP 50,270 for 2024/25) is taxed at the lower CGT rate; anything above is taxed at the higher rate.
- Do I pay CGT on my main home?
- Usually not. Principal Private Residence Relief (PPR) exempts gains on a property that has been your only or main home throughout the ownership period.
- When must I report and pay UK CGT?
- For UK residential property, you must report and pay within 60 days of completion. For other assets, report via Self Assessment by 31 January following the tax year of disposal.