CryptoTax UK · Guide
GBP Conversion for Crypto Tax UK — HMRC Guide
HMRC requires all crypto transactions to be reported in GBP. This guide explains how to convert crypto values to GBP correctly for your UK tax return. Educational only — not tax advice.
Calculate my crypto CGT →Why you need a GBP value for every transaction
UK tax is calculated in GBP. For every crypto acquisition and disposal, you need the GBP value at the time of the transaction. This applies even if you swapped crypto-to-crypto without ever touching fiat.
Acceptable sources for GBP prices
HMRC expects you to use a 'reasonable' GBP value. Acceptable sources include: the exchange rate on the platform where the transaction occurred, reputable price aggregators such as CoinGecko or CoinMarketCap, or the actual GBP amount received if you sold on a GBP exchange. Be consistent in the source you use.
Crypto-to-crypto swaps
When you swap one crypto for another, you need the GBP value of either: the asset you gave up at the time of the swap, or the asset you received — whichever is more readily available.
Stablecoins and USD-pegged assets
Stablecoins pegged to USD (USDC, USDT) are not denominated in GBP. You still need the GBP/USD exchange rate at the time of the transaction to convert USDC/USDT values to GBP.
Frequently asked questions
Does HMRC accept CoinGecko historical prices?
HMRC has not published a list of approved price sources. CoinGecko and CoinMarketCap historical data are widely used by practitioners and are generally considered reasonable sources.
What if a token I traded is no longer listed anywhere?
Use the best available evidence of the GBP value at the time of the transaction — this may include exchange records, contemporaneous screenshots or the value of what you received in the swap.
More UK crypto-tax guides
Educational guidance only. CryptoTax UK is not a regulated tax adviser and the information above does not constitute tax, legal or financial advice. Always confirm your specific position with HMRC or a qualified accountant before filing.