CryptoTax UK · Guide
How to File Crypto Taxes UK — Step-by-Step Guide
Filing your crypto taxes via HMRC Self Assessment can feel daunting. This step-by-step guide walks you through the process from gathering records to submitting your return. Educational only — not tax advice.
Calculate my gains now →Step 1 — Gather all your transaction records
Collect export files from every exchange and wallet you used in the tax year. This includes: spot trade histories, staking and earn records, DeFi activity, airdrops and referral bonuses. You need the date, asset, quantity, GBP value and type of every transaction.
Step 2 — Calculate gains and losses
Apply the HMRC matching rules: first the same-day rule, then the 30-day bed-and-breakfast rule, then Section 104 pooling for the remainder. Calculate the gain or loss on each disposal.
Step 3 — Complete your Self Assessment
Register for Self Assessment if you have not already. Complete form SA100 (the main return) and form SA108 (the capital gains supplement). The deadline for online filing for 2024/25 is 31 January 2026.
Step 4 — Pay any tax owed
Pay any CGT owed by the Self Assessment payment deadline (31 January following the end of the tax year). Late payment attracts interest and penalties.
Frequently asked questions
What form do I use to report crypto gains?
Use SA108 (the Capital Gains supplement to SA100) to report crypto capital gains. Income from staking, mining and airdrops is reported on other sections of SA100.
Do I have to report every single trade?
You report aggregate gains and losses, not every individual trade. However, HMRC may request your full transaction records, so keep them for at least 5 years after the Self Assessment deadline.
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.