Calculate the exact profit or loss on any share trade. Enter how many shares you bought, at what price and what they are worth now — including broker fees and dividends — to see your net return and estimated CGT.
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Every share trade has three components that matter: capital gain (sell minus buy), income (dividends) and costs (stamp duty, broker fees). Net profit is all three combined. Then UK Capital Gains Tax may apply on the gain. Understanding all four numbers — and specifically the break-even price — prevents costly mistakes.
When you buy UK-listed shares, you pay 0.5% Stamp Duty Reserve Tax (SDRT) on the purchase value — automatically collected by your broker. On £2,100 of shares (500 shares at £4.20): stamp duty = £10.50. AIM-listed shares are exempt from stamp duty. ETFs, funds and overseas shares typically have no UK stamp duty. This cost is part of your cost basis for CGT purposes.
The break-even price is the price you need to sell at just to recover your total cost (purchase price × shares + buy fees + stamp duty). It is always higher than the price you paid. On 500 shares at £4.20 with £12 fees and £10.50 stamp duty: break-even = (500 × 4.20 + 12 + 10.50) / 500 = £4.245 per share.
If you hold shares in a general account with a gain, consider "Bed and ISA" — selling outside the ISA (crystallising a gain, using your £3,000 CGT exemption) and repurchasing inside the ISA. Future gains and income then grow tax-free. Must be done within the same tax year and using available ISA allowance.
Stamp Duty Reserve Tax (SDRT) is 0.5% of the total purchase value, rounded up to the nearest penny. It is automatically added to your buy order by your broker. AIM-listed shares, ETFs, funds and overseas shares are typically exempt. Stamp duty is a cost and should be included in your cost basis for CGT calculations.
No. Gains, dividends and income within a Stocks & Shares ISA are completely exempt from CGT and income tax. You can buy, sell and reinvest within the ISA without any tax liability. Only gains from shares held outside an ISA (in a GIA) are subject to CGT.
The Capital Gains Tax Annual Exempt Amount for 2026/27 is £3,000 per person. The first £3,000 of net gains in a tax year is tax-free. Gains above this threshold are taxed at 10% (basic rate taxpayers) or 20% (higher rate) for shares and funds. Unused allowance cannot be carried forward to the next tax year.