Work out the gain on shares, other assets or a second property and the capital gains tax due for 2026/27. The tool uses your other income to split the gain between the basic and higher rate.
Results are estimates for planning. Check the figures before you make a financial or health decision.
How the Capital gains tax calculator works
The calculator follows the usual order of steps:
- Gain = sale price minus purchase price minus allowable costs (fees to buy and sell, and the cost of improvements).
- Losses brought forward are used only as far as needed to bring the gain down to the annual exempt amount, so you do not waste them.
- Annual exempt amount is then taken off. It is an input, so you can change it if it differs for you.
- Basic-rate band left: your other income, less the Personal Allowance (tapered above £100,000), is taxed first. Whatever is left of the £37,700 basic-rate band is available to the gain.
- Gain inside that band is taxed at the basic CGT rate, and the rest at the higher rate. Both rates are editable inputs; check GOV.UK for the current figures.
The asset choice changes the notes shown, not the maths, because shares and residential property now use the same rates. Not modelled: Business Asset Disposal Relief, Private Residence Relief, trusts, part-disposals, losses in the same year and non-residents.
Worked example
Using the default values in the calculator above:
| Input | Value |
|---|---|
| What did you sell | Shares or other assets |
| Sale price | 60000 |
| Purchase price | 30000 |
| Allowable costs | 1500 |
| Annual exempt amount | 3000 |
| Your other income this tax year | 40000 |
| Losses brought forward | 0 |
| Basic-rate CGT rate | 18 % |
| Higher-rate CGT rate | 24 % |
Capital gains tax due: £5,503.80
| Gain | £28,500.00 |
|---|---|
| Losses used | £0.00 |
| Annual exempt amount used | £3,000.00 |
| Taxable gain | £25,500.00 |
| Basic-rate band left | £10,270.00 |
| Gain taxed at 18% | £10,270.00 (tax £1,848.60) |
Tips and common mistakes
Keep records of what you paid, including fees and improvement costs, because every allowable cost reduces the gain. Include all your income for the year, not only your salary, since the amount of basic-rate band left decides the split. If you sold several assets, add the gains and losses together first and enter the net figures. Residential property gains usually have to be reported and paid within 60 days of completion, so do not wait for your tax return; check GOV.UK for the current deadlines and for how to report a loss.
Frequently asked questions
Do I pay capital gains tax on my main home?
Usually not, because Private Residence Relief covers a home you have lived in as your main residence. This calculator does not apply that relief, so it suits second homes, investment property and other assets. Check GOV.UK for the conditions.
Is the annual exempt amount per person?
Yes. Each person has their own annual exempt amount, so a couple who jointly own an asset can each use theirs. Unused allowance cannot be carried forward to later years.
How are capital losses used?
A loss reduces a gain. Losses carried forward from earlier years are used only to reduce this year’s gain to the annual exempt amount. Losses must be reported to HMRC to be carried forward.
Guides that help
- Capital gains tax explained: rates, allowance and how to work it out
- UK income tax explained: bands, allowance and how it's worked out
- Stamp Duty, LBTT and LTT explained