Crypto Tax Calculator UK 2026

Calculate your UK Capital Gains Tax on cryptocurrency using HMRC rules. Applies Section 104 pool averaging, same-day rule, and 30-day bed-and-breakfast rule.

Cryptocurrency is subject to Capital Gains Tax in the UK, and HMRC is actively pursuing non-compliant taxpayers. In 2024, HMRC sent nudge letters to over 50,000 crypto holders identified through data-sharing agreements with major exchanges. The CGT annual exempt amount was reduced to £3,000 in 2024/25, meaning more crypto investors now have a tax liability.

HMRC applies specific share pooling rules to crypto assets. The same-day rule matches disposals against acquisitions on the same day. The 30-day bed-and-breakfast rule matches against repurchases within 30 days. All remaining tokens are pooled using Section 104 averaging. These rules mean you cannot simply use a FIFO method.

Enter your buy and sell transactions and the calculator applies all three HMRC rules to determine your taxable gain. It then calculates the CGT due based on your income tax band, either 18% (basic rate) or 24% (higher/additional rate). These are the rates for disposals on or after 30 October 2024; earlier disposals used 10% and 20%.

How it works

  1. Enter your annual income to determine your CGT rate.
  2. Add your cryptocurrency buy and sell transactions with dates and amounts.
  3. View the calculated gain after applying HMRC pooling rules and the CGT due.

Written by the CalcStack team

Figures for the 2026/27 UK tax yearlast verified Sources: HMRC cryptoassets tax guidance, GOV.UK Capital Gains Tax

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Frequently asked questions

How is cryptocurrency taxed in the UK?
HMRC treats cryptocurrency as a capital asset. When you sell, swap, or spend crypto, you may owe Capital Gains Tax on any profit. For 2026/27 the CGT rates are 18% where the gain falls within your basic rate band and 24% above it. The old 10% and 20% rates applied only to disposals made before 30 October 2024. Mining and staking rewards are treated as income and taxed at your income tax rate.
What is the Section 104 pool for crypto?
The Section 104 pool is the method HMRC requires for calculating cost basis. All tokens of the same type are pooled together, and the cost basis is the average cost per token. When you sell, the cost basis is calculated from this average. This prevents you from cherry-picking specific tokens to reduce tax.
What is the same-day rule?
The same-day rule overrides the Section 104 pool. If you buy and sell the same crypto on the same day, the cost basis is matched to the same-day purchase first. This prevents a "wash sale" where you sell and immediately rebuy at a similar price to crystallise a loss.
What is the 30-day bed and breakfast rule?
The bed and breakfast rule (30-day rule) prevents you from selling crypto to crystallise a loss and then rebuying within 30 days. If you rebuy the same crypto within 30 days of selling, the cost basis of the sale is matched to the repurchase price, not the Section 104 pool average.
Do I pay tax on crypto swaps?
Yes. Swapping one cryptocurrency for another (e.g., BTC to ETH) is a taxable disposal. You are deemed to have sold the first crypto at its market value and purchased the second. Capital Gains Tax applies to any gain on the disposal of the first cryptocurrency.
Is there a tax-free allowance for crypto?
Yes. The annual CGT exempt amount is £3,000 for 2026/27. This covers all capital gains, not just crypto. So if you have gains from shares and crypto, the £3,000 exemption is shared across all disposals. Any gain above this is taxed at 18% or 24%.
How is crypto mining and staking taxed?
Mining and staking rewards are treated as income by HMRC. The market value at the time you receive the tokens is taxable as miscellaneous income. When you later sell those tokens, you also owe CGT on any gain above the cost basis (the value at the time of receipt).
Do I need to report crypto on my tax return?
You must report on your Self Assessment return if your total gains exceed the £3,000 annual exempt amount, or if your total proceeds from all chargeable disposals exceed £50,000, even where no tax is due. The proceeds test has been a fixed £50,000 since 2023/24; the old rule of four times the annual exempt amount no longer applies. You also need to report if you are already required to file a return for another reason. Even if you made a loss, claim it so it can be carried forward against future gains.
Can I offset crypto losses against gains?
Yes. Crypto losses can be offset against gains in the same tax year. Unused losses can be carried forward indefinitely. You must report losses to HMRC within 4 years. Strategic loss harvesting (selling losing positions) before the tax year end can reduce your CGT bill.
How does HMRC know about my crypto?
HMRC has data-sharing agreements with major UK crypto exchanges. They receive transaction data from Coinbase, Binance, Kraken, and others. HMRC has sent "nudge letters" to crypto holders encouraging voluntary disclosure. Non-disclosure can result in penalties of up to 200% of the tax owed.

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Also useful: Capital Gains Tax Calculator·Self-Assessment Tax Estimator·UK Take-Home Pay Calculator Pro

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