The UK tax year ends on 5 April. Here’s a checklist for crypto investors to get organised before the deadline.
Before 5 April (Tax Year End)
| Task | Why |
|---|---|
| Calculate all gains and losses | Know your CGT position |
| Harvest losses | Offset gains before year-end |
| Use your CGT allowance | £3,000 for 2025-26 |
| Check staking and airdrop income | Under £1,000 trading allowance? |
| Review your records | Complete and accurate? |
| Check exchange statements | Match your records |
| Identify any missing transactions | Fill gaps now |
After 5 April (Tax Year Ended)
| Task | Deadline |
|---|---|
| File self assessment | 31 January (following year) |
| Pay CGT due | 31 January |
| Report gains on property (if applicable) | Within 60 days |
| Keep records for 6 years | HMRC can investigate |
CGT Allowance Check
| Year | Allowance | Check |
|---|---|---|
| 2025-26 | £3,000 | Gains under this? No tax due |
| Gains over £3,000 | Taxable | Calculate and report |
If your total disposals exceed £50,000, you must report even if gains are under the allowance.
Loss Harvesting Checklist
| Task | Details |
|---|---|
| Identify losing positions | Check your portfolio |
| Sell before 5 April | Realise the loss this tax year |
| Don’t buy back within 30 days | B&B rules apply |
| Offset against gains | Reduce tax bill |
| Carry forward unused losses | Report within 4 years |
Income Check
| Type | Allowance | Action |
|---|---|---|
| Staking rewards | £1,000 trading allowance | Sum total value |
| Airdrops | £1,000 trading allowance | Value when received |
| Lending interest | £1,000 trading allowance | Track each payment |
| Mining income | £1,000 trading allowance | Report if over |
Record Keeping Check
| Record | Have It? |
|---|---|
| Transaction history from all exchanges | |
| Wallet addresses used | |
| DeFi interaction records | |
| Staking and lending logs | |
| NFT purchase and sale records | |
| Bank statements showing deposits | |
| Gas fee records | |
| Cost basis calculations |
Common Mistakes at Year-End
| Mistake | Fix |
|---|---|
| Forgetting small transactions | Include everything |
| Missing DeFi activities | Track lending, staking, swaps |
| Not reporting losses | Losses offset future gains |
| Ignoring token-to-token trades | Each trade is a disposal |
| No records for cost basis | Calculate before you need it |
Bottom Line
The tax year ends 5 April. Calculate gains, harvest losses, and check your income allowances before the deadline. Keep complete records. Report gains over £3,000 and disposals over £50,000. File by 31 January. If you’re unsure, get professional advice — HMRC is increasingly active on crypto.
What matters most before 5 April
The single most important action is calculating your total crypto gains and losses for the tax year, because you cannot file accurately without those figures. Harvesting losses before the deadline is equally valuable — selling positions at a loss reduces your tax bill and frees up your allowance for future gains. Do not forget that every token-to-token trade counts as a disposal for CGT, so even if you never touched pounds sterling, you may owe tax. If your total disposals exceed £50,000 you must report them even when gains fall below the £3,000 allowance. Finally, check that your records are complete: transaction histories from every exchange, wallet addresses, DeFi interactions, staking logs, and gas fee records all need to be in order before you file.
Getting your records in order
Start by exporting transaction histories from every exchange you used during the tax year — most platforms offer CSV downloads covering the full period. Cross-reference those exports against your own records, checking for discrepancies in amounts, dates, and fees. If you used DeFi protocols, gather wallet-level data from a portfolio tracker such as Koinly, CoinTracker, or TokenTax, which can import on-chain transactions and calculate cost basis automatically. Make sure you have records of gas fees paid, as these typically reduce your gain. Finally, confirm you know the cost basis for every asset you still hold — HMRC may query it if you are selected for an investigation, and the burden of proof is on you.
Common questions from crypto investors
Q: Do I pay capital gains tax on every crypto-to-crypto trade? A: Yes. Each swap from one cryptocurrency to another is a disposal for CGT purposes, even if you never converted to pounds sterling. You need to calculate the gain or loss on every trade and include it in your Self Assessment.
Q: What happens if I miss the 31 January filing deadline? A: HMRC charges an initial £100 penalty for late filing, with further penalties of £10 per day after three months (up to 90 days) and a percentage of any unpaid tax after six and twelve months. Filing early, even if you cannot pay the full amount, avoids the escalating penalties.
Q: Can I offset crypto losses against other types of income? A: Capital losses can only be offset against capital gains, not against salary or other income. However, you can carry unused losses forward to future tax years and offset them against gains in those years.
Q: Does HMRC actually check crypto transactions? A: HMRC has invested heavily in data-sharing agreements with UK exchanges and uses third-party blockchain analytics tools. They can trace on-chain transactions, so assuming crypto gains are invisible is a significant risk.
Further reading and useful references
HMRC’s manual on crypto assets is the definitive UK guidance on how different transactions are taxed. The official Self Assessment guidance covers filing deadlines, payment methods, and penalty details. Portfolio trackers such as Koinly, CoinTracker, and TokenTax can automate much of the record-keeping process described in this article. For a broader understanding of how CGT works, our personal finance section covers allowances, loss harvesting, and tax-efficient investing strategies. The MoneySavingExpert guide to Self Assessment is a practical walkthrough of the filing process itself.
Building good habits for future tax years
The best time to start organising your crypto tax records is at the beginning of the tax year, not at the end. Maintain a running spreadsheet or use a portfolio tracker that calculates cost basis in real time, so you are never scrambling to reconstruct transactions months later. Set a quarterly reminder to export exchange data and check that your wallet records are complete. If you actively trade or use DeFi, consider using a tax-literate accountant from the start — the cost of professional advice typically pays for itself by identifying legitimate deductions you might miss. Keeping six years of records is the minimum HMRC requires, and the peace of mind is worth the small amount of storage space.
Actions to take this week
Start by logging into each exchange you used during the tax year and downloading your full transaction history as a CSV file — most platforms offer this under account settings or tax reports. If you used DeFi, connect your wallet addresses to a portfolio tracker to capture on-chain transactions that exchanges do not record. Run a quick gain-and-loss summary for the year so you know your CGT position before the deadline. If your gains exceed £3,000, set aside the estimated tax bill now rather than waiting until January when cash flow may be tighter. For anything beyond a simple portfolio, speak to a tax adviser who understands crypto — the cost of getting it wrong is typically higher than the cost of getting help.