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Capital Gains Tax Calculator UK
Estimate UK Capital Gains Tax on shares, funds, property or other taxable assets after costs, the annual exemption and your remaining basic-rate band.
2026/27 exemption: £3,000
Rates: 18% and 24%
Simplified estimate
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Calculate your estimated CGT
Enter the sale proceeds, original cost, allowable costs and your taxable income. The result updates automatically.
What you sold the asset for.
What you paid for the asset.
Broker, legal or selling costs that may be allowable.
Used to estimate how much basic-rate band is left.
Used for guidance notes. The 2026/27 rates here are 18% and 24%.
This version uses 2026/27 assumptions.
The 2026/27 individual exemption is £3,000.
How to use this calculator
- Enter the amount you sold the asset for.
- Enter what you originally paid and any allowable buying or selling costs.
- Add your annual taxable income so the calculator can estimate your remaining basic-rate band.
- Review the gross gain, taxable gain and estimated CGT.
What your CGT result means
The estimated CGT figure is the tax that may be due after deducting your original cost, allowable costs and annual exempt amount.
This is a simplified calculator. It does not cover every relief, previous loss, spouse transfer, carried interest rule or special asset category.
Important: if the sale involves residential property, a business asset, crypto, non-UK status, trusts or previous losses, get professional tax advice before relying on an estimate.
Planning around taxable investments?
Compare tax-efficient options such as ISAs and pensions before deciding where future savings and investments should sit.
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How Capital Gains Tax works
Capital Gains Tax is charged on the profit you make when you sell or dispose of certain assets. The gain is normally the sale proceeds minus the original cost and any allowable buying or selling costs.
For individuals, the 2026/27 Capital Gains Tax annual exempt amount is £3,000. That means only gains above the available exemption are potentially taxable.
The taxable gain is added on top of your taxable income to decide how much falls within the remaining basic-rate band. Gains within the basic-rate band are taxed at 18%, while gains above that band are taxed at 24% for gains made from 6 April 2026.
Assets held inside an ISA are normally sheltered from CGT. That is why the ISA allowance can matter for investors who expect taxable gains outside an ISA.
What affects your CGT estimate
- Sale proceeds: a higher sale price usually increases the gain.
- Original cost: the amount you paid for the asset reduces the gain.
- Allowable costs: some buying and selling costs may reduce the taxable gain.
- Annual exemption: the first £3,000 of gains may be covered by the 2026/27 exemption if available.
- Taxable income: your income affects how much of the gain falls into the basic or higher CGT rate.
- Tax wrapper: gains inside an ISA are normally outside CGT.
Capital Gains Tax calculator formula
The calculator first works out the gain, then deducts the annual exemption and splits the taxable gain across the remaining basic-rate band.
gain = sale_proceeds - original_cost - allowable_costs
annual_exempt_amount = £3,000
taxable_gain = gain - annual_exempt_amount
taxable_income_after_allowance =
max(0, annual_income - £12,570)
basic_band_remaining =
max(0, £37,700 - taxable_income_after_allowance)
basic_rate_gain = min(taxable_gain, basic_band_remaining)
higher_rate_gain = taxable_gain - basic_rate_gain
estimated_CGT =
basic_rate_gain × 18%
+ higher_rate_gain × 24%
CGT quick reference
Figures shown are for the 2026/27 tax year.
| Item | 2026/27 figure | How this calculator uses it |
|---|---|---|
| Annual exempt amount | £3,000 | Deducted from the gross gain if the exemption toggle is switched on. |
| Basic-rate CGT | 18% | Applied to taxable gains within the remaining basic-rate band. |
| Higher-rate CGT | 24% | Applied to taxable gains above the remaining basic-rate band. |
| Personal Allowance used for band estimate | £12,570 | Used to estimate taxable income before checking the basic-rate band. |
Capital Gains Tax calculator FAQs
What is the CGT allowance for 2026/27?
For individuals, the Capital Gains Tax annual exempt amount is £3,000 for the 2026/27 tax year.
What CGT rates does this calculator use?
It uses 18% for taxable gains within the remaining basic-rate band and 24% for gains above that band for gains made from 6 April 2026.
Do I pay CGT if my gain is below the allowance?
If your total taxable gains for the year are below the available annual exempt amount, your estimated CGT may be zero.
Does this calculator include losses and reliefs?
No. This is a simplified estimate and does not model all reliefs, carried-forward losses, spouse transfers or Business Asset Disposal Relief.
Does CGT apply inside an ISA?
Gains inside an ISA are normally sheltered from Capital Gains Tax. This calculator is for assets held outside tax wrappers.
Key terms used in this calculator
These glossary pages explain the main terms used when estimating gains, allowances and tax-efficient investment wrappers.