For shares and funds, at 2026/27 rates
When you sell shares outside an ISA or pension for more than you paid, the profit is a capital gain and HMRC may tax it. You get an annual allowance first, and only what’s left above it is taxed.
The rate depends on your income, because gains sit on top of it — which means one disposal can be taxed at two different rates. This calculator works that split out properly rather than applying a single flat rate.
Total proceeds from the sale
Purchase price plus any dealing charges
Salary and other taxable income this year. This decides how much of your gain is taxed at the lower rate.
Capital losses from this year or carried forward
Gains you've already realised this year. The allowance is £3,000 for 2026/27.
Capital gains tax due
£1,260
An effective rate of 12.6% on your £10,000 gain
Taxed entirely at the basic rate
Estimate for guidance only, based on 2026/27 rates for shares and other non-property assets. Residential property, business asset disposal relief and non-UK residency are not covered. This is not tax advice.
This is the part most calculators skip. Capital gains are treated as the top slice of your income for the year — they stack on top of your salary rather than being taxed in isolation.
So the rate isn't simply “18% if you're a basic rate taxpayer”. It depends how much of your basic rate band is left after your income. Earn £45,000 and only £5,270 of band remains, so a £7,000 gain gets split: the first £5,270 at 18% and the remainder at 24%.
A flat-rate calculator would tell you the whole gain is taxed at 18% and understate your bill. That's why this one asks for your income.
The sequence matters, because it changes the answer:
One subtlety worth knowing: the annual exempt amount reduces the gain you're taxed on, but it does not use up any of your basic rate band. Only your income does that.
Our ISA transfer calculator works out whether the tax cost of moving shares into an ISA pays for itself, and the compound growth calculator shows what sheltering them is worth over time.
It handles shares, funds and other non-property assets at 2026/27 rates. It does not cover residential property, business asset disposal relief, non-UK residency, or assets held in trust. Those follow different rules and different rates.
It also assumes a straightforward acquisition cost. If you bought the same shares on several dates you may need HMRC's share pooling rules to work out the cost, which this doesn't do for you.
For 2026/27 the rates on shares are 18% for gains falling within your basic rate band and 24% above it. Your gain is treated as the top slice of your income, so if it straddles the higher rate threshold you pay both rates on different parts of the same gain. You also get an annual exempt amount of £3,000, deducted before any tax is worked out.
Yes, and this is the most commonly missed part. Capital gains stack on top of your income. If your salary already uses your entire basic rate band, the whole gain is taxed at 24%. If your income is low, more of the gain falls into the 18% band. That is why this calculator asks for your other income rather than asking you to declare a tax band.
No. The annual exempt amount reduces the gain you are taxed on, but it does not consume any of your basic rate band. Only your income does that. This trips up a lot of calculators and produces a bill that is too low.
Split a large disposal across two tax years to use two annual allowances. Transfer assets to a spouse or civil partner before selling, since transfers between them are tax-free and they have their own allowance and basic rate band. Realise losses on other holdings in the same year to offset the gain. And hold future investments inside an ISA, where gains are sheltered permanently.
There is no tax to pay. You should still report the loss to HMRC, because it can be offset against gains in the same tax year or carried forward indefinitely against future gains. You must claim it within four years of the end of the tax year in which it arose, otherwise it is lost.
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