Capital gains tax, calculated with the working shown.

Enter a gain, get the tax, and see every step of the arithmetic, the allowance applied, your basic rate band split, the rate on each slice, your effective rate, and what the same gain would cost split across two tax years. Correct figures for each tax year back to 2021 to 2022, including the mid-year rate change of 30 October 2024 that most calculators ignore. Everything runs on this page, nothing you type goes anywhere.

Tax year allowance and rates change
after costs of acquisition
optional
sets your band
The working

Two figures and the full working appears, with nothing invented in the meantime.

    Assumes an individual with the standard personal allowance, assets other than residential property, no reliefs, and current frozen income tax thresholds. For 2024 to 2025 the allowance and losses are set against post-October gains first, the ordering HMRC permits and the one that favours you. An estimate for orientation, not a filing document. Runs on this page, nothing transmitted.

    Do not know the gain yet? The crypto tax calculator takes your actual buys and sells and works it out under the pooling rules first. Working out the profit before the tax? The crypto profit calculator handles fees, break-even and target prices. For what the allowance is doing to your planning this year, see the £3,000 annual exempt amount in 2026 to 2027.

    This was the easy part.

    Every calculator on the internet, including this one, asks you to already know your gain. The actual work of crypto tax is computing that gain, matching every disposal under same day, 30 day and section 104 pooling rules across every wallet and exchange you have ever used. The crypto tax calculator does that matching on this site for one token typed by hand. The full app does it across every wallet and exchange, on your machine, with the rule named on every disposal, free under 1,000 transactions.

    Compute my actual gains

    Calculator questions.

    How is UK capital gains tax calculated on crypto and shares
    Net gains for the tax year, minus the annual exempt amount (£3,000 currently), are taxed at 18% where they fit inside your unused basic rate band and 24% above it. Older years used different allowances and rates, and this calculator carries the correct historic figures per year.
    Is this calculator accurate for my actual tax return
    It computes the tax on a gain you already know, using the correct year figures. The genuinely hard part of crypto tax is computing the gain itself under the matching rules, same day, 30 day, then section 104 pooling, which is what the full app does, free under 1,000 transactions.
    Does this calculator send my numbers anywhere
    No. It runs entirely on this page in your browser. Nothing you type is transmitted, stored or logged, which you can verify in your browser network tab. Even the share link keeps your figures in the fragment, the part of a URL after the # symbol, which browsers never send to a server.
    What happened to capital gains tax rates on 30 October 2024
    Rates on assets other than residential property rose from 10% and 20% to 18% and 24% from 30 October 2024, mid tax year, so 2024 to 2025 disposals are taxed under two regimes depending on their date. The calculator handles the split.
    What is my effective rate of capital gains tax
    The tax you actually pay divided by your total gain. It is always lower than the headline rate, because the annual exempt amount comes off first and part of the gain may sit inside your basic rate band. The calculator shows it on every result, which is the number most people are really asking for.
    Does splitting a disposal across two tax years save tax
    Often, yes. Each tax year carries its own annual exempt amount, so a gain realised across two years gets two allowances instead of one, and more of it can fall inside the basic rate band. The calculator prices that comparison for you. The disposals have to be genuine and correctly dated, a sale on 5 April and one on 6 April fall in different years.

    Figures verified 21 August 2026 against HMRC's published allowances, rates, historic rates and allowances and income tax bands. General information, not personal tax advice, see a vetted professional for your own affairs.