How to use the calculator
You need to input your income as this determines what rate you will pay on your gains. In 2024-25 basic-rate taxpayers are taxed at 10pc, while higher-rate taxpayers pay 20pc. From next April, these rates will increase to 18pc and 24pc respectively, equalising the rates with the residential tax rates.
Then input how much you bought and sold the investment for to calculate the gain or profit you have made.
Hit calculate and you will see your capital gains bill in this tax year, the previous tax year, and the difference in profit.
How the calculator works
This calculation assumes you have your full CGT allowance – £3,000 in the 2024-25 tax year – intact. If you have lost money on capital gains taxable investments in the past, you might be able to offset against profit.
How will my capital gains tax bill be calculated?
To work out your potential liability, you need to compare the amount you initially paid for the investment with the amount you are likely to get when you sell it.
You can deduct expenses – such as stockbrokers’ fees and stamp duty on share purchases – from the gain. You may also qualify for various tax breaks, such as business asset disposal relief, which means you pay a lower rate of CGT or none at all.
It’s also possible to offset losses from previous tax years, or from the sale of other properties, from your overall gain.
The gain you’re left with is the difference between your costs and losses, and what you get when you sell.
For example, if you bought shares in ABC Company (and did not buy them inside an Isa or pension) for £5,000 and sold them later for £25,000, you’ve made a gain of £20,000 (£25,000 minus £5,000).
If you haven’t already used up your capital gains allowance you can offset that, so in 2024-25 your taxable gain would be £17,000.
If you are a higher-rate income taxpayer, the 20pc rate would apply, producing a bill of £3,400 leaving you with a gain of £16,600.