Crypto Capital Gains Tax Calculator
Calculate UK CGT on Bitcoin, Ethereum and all crypto disposals. Supports multiple buys and sells using the HMRC Section 104 average cost basis pool.
How HMRC treats crypto
- • HMRC treats crypto as a capital asset, not currency. Every disposal — sale, swap, or payment — is a taxable event.
- • The UK uses a Section 104 pool: all units of the same token share a pooled average cost. This calculator implements that automatically.
- • Same-day and Bed & Breakfast (30-day) rules override the pool — consult an accountant if you trade frequently.
- • Lost or stolen crypto may qualify as a negligible value claim — contact HMRC or a tax adviser.
Crypto Transactions
Uses HMRC Section 104 pool (average cost basis)
| Type | Date | Quantity | Total Value (£) | |
|---|---|---|---|---|
| BUY | £ |
Tax Details
Determines your CGT rate band
Other disposals already in 2025/26
Add transactions to see your CGT result
Crypto CGT 2025/26 — Key Facts
Since HMRC began treating cryptocurrency as a capital asset, UK investors must declare all disposals through Self Assessment. Following the October 2024 Autumn Budget, CGT rates on crypto moved from 10%/20% to 18%/24%. The annual exempt amount remains £3,000. If total disposals exceed £12,000 in a tax year, you must report even if no tax is owed. Keep records of every transaction — HMRC can request these up to 5 years after your Self Assessment deadline.
Worked examples — crypto CGT
Selling Bitcoin for fiat: higher rate taxpayer
Bought 0.5 BTC for £9,000 total (using Section 104 pool average cost). Sold for £23,500.
Gain: £23,500 − £9,000 = £14,500. Less £3,000 allowance = £11,500 taxable. At 24%: £2,760 CGT.
Report via Self Assessment by 31 January following the tax year end.
Crypto-to-crypto swap (disposal event)
Swapped ETH worth £4,200 (bought for £1,800) for another token. HMRC treats this as a disposal of ETH at market value.
Gain: £4,200 − £1,800 = £2,400. Under £3,000 allowance — £0 CGT this year, but must still be declared if total disposals exceed £12,000.
Who is this calculator for?
UK crypto investors calculating CGT on Bitcoin, Ethereum, altcoin, and DeFi disposals. Useful for anyone selling crypto for fiat, swapping between tokens, spending crypto, or receiving staking/mining rewards. Also useful for accountants preparing Self Assessment returns with cryptocurrency transactions.