Your first crypto tax return
Self Assessment can feel daunting the first time you include crypto. This path takes you from records to filing in the order most people need — without skipping the steps HMRC cares about.
Quick answer
Gather records → check if you must report → calculate gains and income → complete SA108 crypto boxes → submit Self Assessment by 31 January. Register by 5 October if you are new to Self Assessment.
- Step 1 When to report
Confirm you need to file
UK reporting rules for 2025/26 — £3,000 CGT allowance, £50,000 proceeds threshold, income triggers and CARF.
- Step 2 Record keeping
Download the CSV template if needed
What transaction records UK crypto holders must keep for HMRC — dates, sterling values, fees and a free downloadable CSV template.
- Step 3 CGT worked example
Understand pooling in plain numbers
Step-by-step Capital Gains Tax calculation for UK crypto — buy, swap and sell with Section 104 pooling in plain numbers.
- Step 4 Tax software guide
Optional: software for many transactions
Compare crypto tax tools for UK Self Assessment — HMRC pooling, SA108 output, and what HMRC does not endorse.
- Step 5 SA108 crypto boxes
Map totals to the right boxes
Which SA108 boxes to use for UK crypto gains and losses in 2025/26 — proceeds, costs, gains, losses and income.
- Step 6 Self Assessment
Register, file and pay
How to register for Self Assessment and report crypto gains and income to HMRC — deadlines, forms and records.