UK Crypto Tax 2025/26 Checklist

1. Collect every transaction

HMRC expects a complete record — on-chain wallets, exchange trades, staking rewards, airdrops and DeFi, all of it.

• Export CSVs from every exchange you used in 2025/26

  Coinbase, Kraken, Binance, Bybit, Revolut — log in and download the full-year transaction CSV. If the account is closed, email their support for an export while you still can.
• List every on-chain wallet address you own

  Ethereum, Solana, Bitcoin, BSC, Polygon, Arbitrum, Optimism, Base, Avalanche. Include any hardware wallet addresses and any address your cold storage ever sent to or received from.
• Note staking, lending and DeFi positions

  Staking rewards are taxed as income when received (at GBP market value), and as CGT on later disposal. DeFi is trickier — write down every pool you entered and exited.
• Flag airdrops, NFT mints and giveaways

  Free tokens are income at the GBP value the day you could first sell them. Missed airdrops are one of the top HMRC audit triggers.

2. Convert everything to GBP

HMRC reports are in sterling. Every disposal needs a GBP value at the time of the trade.

• Use spot rates from a reputable source

  CoinGecko, Kraken historical, or HMRC's own rates. Be consistent — pick one source and stick to it for the full tax year.
• Crypto-to-crypto is a disposal

  Swapping ETH for USDC triggers a CGT disposal of the ETH at its GBP value, and an acquisition of USDC at the same GBP value. This catches a lot of people out.
• Fees reduce your gain

  Exchange fees, gas and network fees attached to a disposal are allowable costs that reduce your capital gain. Keep them, don't ignore them.

3. Apply HMRC's matching rules (in order)

When you dispose of crypto, HMRC has a strict three-step matching order. Miss a step and your return is wrong.

• Same-day rule — match disposals to same-day acquisitions first

  Any crypto of the same type acquired on the same day as the disposal is matched first.
• 30-day bed-and-breakfast rule — then the next 30 days

  Match any remaining disposal to acquisitions of the same asset in the 30 days after the disposal.
• Section 104 pool — everything else

  What's left is matched against the averaged pooled cost of all prior acquisitions. The pool's average cost updates with every buy.

4. Apply the allowance and compute tax

• Deduct the £3,000 annual exempt amount

  The 2025/26 CGT allowance is £3,000 per individual. Deduct it from your net taxable gains. If your total gains are under £3,000, you owe no CGT on crypto.
• Apply the correct CGT rate

  After the October 2024 Budget: 18% for basic-rate taxpayers, 24% for higher- and additional-rate. Your rate depends on your total taxable income including the gain.
• Offset prior-year losses

  Carried-forward losses can reduce your taxable gain — but only if they were claimed within four years of the tax year of the loss.

5. File and keep records

• Self Assessment SA108 — Capital Gains Summary

  Crypto goes on the SA108 supplementary pages. You'll need total disposal proceeds, total allowable costs, and the net gain or loss.
• Online deadline: 31 January 2027

  Paper returns are due 31 October 2026; online 31 January 2027. Tax owed is due the same day as the filing deadline.
• Keep records for at least 5 years

  HMRC can ask to see your workings for five years after the 31 January filing date. A CSV of every transaction plus a signed PDF of your calculations is the safest bet.

6. Common traps to avoid

• Thinking 'I only lost money so I don't need to file'

  Wrong. File the loss — you can carry it forward and offset against future gains. Unclaimed losses after four years are gone.
• Moving between your own wallets is NOT a disposal

  Send from Coinbase to your Ledger? Not taxable. But the network fee paid in crypto is a tiny disposal of that fee asset.
• Lost wallets / rugpulls can be a negligible-value claim

  If a token has become worthless, you may be able to make a negligible-value claim and realise the loss without actually selling. Keep evidence.
• Gifting crypto (except to a spouse) is a disposal

  Giving crypto to a friend, child or charity is a disposal at market value. Gifts to a spouse or civil partner are nil-gain, nil-loss.