Capital gains tax calculator UK: shares, crypto and property

Selling shares, funds, a business or other assets above the annual exempt amount of £3,000 triggers capital gains tax at 18% or 24%. The calculation runs in a fixed order: add up the year's gains, take off this year's losses, take off the £3,000 exempt amount, then add what is left to your taxable income. Gain that fits in what is left of your £37,700 basic-rate band after your taxable income is charged at 18%, and gain above it at 24%. The £3,000 allowance is per person and does not carry forward.

HMRC matches each sale against your purchases in a set order: shares bought the same day come first, then shares bought in the following 30 days, then the Section 104 pool that averages the cost of everything else you hold. The calculator applies the same order when you import a broker CSV, so a repurchase inside 30 days does not create the loss you expected.

A home that was your main residence for the whole time you owned it is exempt from capital gains tax. If it was your main home for only part of the time, Private Residence Relief covers the fraction of the gain that matches the months you lived there. The last 9 months of ownership always count as living there, even if you had already moved out. The calculator takes the months you lived in the property before that final period, adds the final 9, divides by the months you owned it and exempts that share of the gain.

Tick the main home box for a home you lived in throughout. If you lived in it for part of the time, leave the box empty and type the months you lived there before the final period instead. Months you lived there inside the final period are already covered by it.

A property that was never your main home, or was let out, carries no Private Residence Relief for those periods. The gain is charged at the same 18% and 24% rates as shares. UK residential property sales have a tighter deadline than other assets: you report the sale and pay the tax within 60 days of completion, not in your next Self Assessment return.

Costs of buying and selling, such as stamp duty, legal fees and estate agent fees, and improvements that add to the property come off the gain. Repairs and redecoration do not. Enter each on the property card and the calculator subtracts them before the tax.

HMRC treats crypto as a chargeable asset. Selling a coin, swapping it for another, spending it on goods and giving it away all count as disposals. Each token is matched with the same three rules as shares: same-day purchases, then purchases in the following 30 days, then the Section 104 pool for that token.

Import your exchange CSVs and the calculator applies the matching order and the £3,000 annual exempt amount across all your disposals in the year.

Gains that qualify for Business Asset Disposal Relief are charged at 18% in the 2026/27 tax year, up to a lifetime limit of £1,000,000 of qualifying gains. Tick the relief box on a sale that qualifies and enter the gains you claimed in earlier years in section 3, and the calculator tracks the limit for you. Gains above the limit are charged at the normal 18% and 24%.

Chattels, meaning personal possessions such as a watch or a painting, are exempt when they sell for £6,000 or less. Above that the gain is capped at five thirds of the excess over £6,000.

Losses in the year are set against that year's gains before the annual exempt amount is used. If your losses are larger than your gains, the unused loss carries forward with no time limit, but you must report it to HMRC within four years of the end of the tax year in which you made it. Enter the losses you brought forward in section 3 and the calculator uses them against the gains that would be charged at the highest rate first.

The tax year runs from 6 April to 5 April. Report gains on a Self Assessment return: the online deadline is 31 January after the end of the tax year, so the 2026/27 tax year is due by 31 January 2028, and the tax is due the same day. A sale of UK residential property is the exception, with its 60 day limit from completion.

The calculator covers one tax year at a time. A sale dated outside the year you have open is left out of the numbers, so open a return for each tax year you sold in.