Tax year 2025/26 — filing window now open

UK Crypto Tax 2025/26

The tax year ended 5 April 2026. If you swapped, sold, or spent crypto in the past 12 months, HMRC expects a return. Here's exactly what you owe — and how to calculate it in minutes.

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Key dates for 2025/26

Tax year ended
5 April 2026
Gains & losses through this date count for 2025/26.
Paper return deadline
31 Oct 2026
Only if you file on paper — most people file online.
Online deadline & payment
31 Jan 2027
Return filed and tax paid. £100 penalty starts one minute later.

Rates & allowance

Annual exempt amount
£3,000
First £3,000 of net gains each tax year is tax-free. Can't be carried forward.
CGT rate (after allowance)
18%
basic rate
/
24%
higher rate
Rates rose from 10%/20% at the October 2024 Budget — many first-time filers aren't aware.

The three HMRC matching rules

1. Same-day rule

If you buy and sell the same token on the same day, those transactions are matched against each other first — regardless of order.

2. 30-day rule (“bed & breakfasting”)

A sale followed by a re-purchase of the same token within 30 days is matched against the re-purchase, not your pool. This stops people crystallising losses artificially.

3. Section 104 pooling

Anything left over goes into a weighted-average pool per token. Your gain on a disposal uses the pool's average cost — not FIFO, not LIFO.

These three rules must be applied in order. Getting the order wrong is the most common mistake on DIY crypto returns — and it can swing the final tax bill by hundreds.

Filing with CryptoLens — in under 10 minutes

  1. 1
    Paste your wallet addresses

    One 0x address covers all 7 EVM chains we support — Ethereum, BSC, Polygon, Arbitrum, Optimism, Base and Avalanche. Add a Solana address separately. No private keys, ever.

  2. 2
    Import exchange CSVs if you use Binance, Coinbase or Kraken

    We merge on-chain + exchange data into one timeline. Inter-wallet transfers are automatically de-duplicated so they don't look like taxable events.

  3. 3
    We apply the matching rules

    Same-day → 30-day → Section 104, in order, per token. The £3,000 allowance is deducted at the end. Your CGT owed and any carried-forward loss is shown line by line.

  4. 4
    Download the HMRC-ready PDF + CSV

    Hand the PDF to your accountant or copy the totals straight into boxes 14–17 of the Capital Gains supplement (SA108). Pro trial covers this — free for 7 days.

Frequently asked

When is the UK crypto tax deadline for the 2025/26 tax year?

Online Self Assessment returns for the 2025/26 tax year must be filed by 31 January 2027, and any tax owed is due the same day. Paper returns are due earlier, by 31 October 2026.

What is the Capital Gains Tax allowance for 2025/26?

The annual CGT tax-free allowance for individuals is £3,000 for the 2025/26 tax year. Only gains above this amount are taxable.

What are the CGT rates on crypto for 2025/26?

After the October 2024 Budget, crypto CGT rates align with shares: 18% for basic-rate taxpayers and 24% for higher- and additional-rate taxpayers, applied to gains above the £3,000 annual exempt amount.

What counts as a disposal?

HMRC treats the following as taxable disposals: selling crypto for GBP (or any fiat), swapping one token for another (including into stablecoins), spending crypto on goods or services, and gifting crypto to anyone other than a spouse or civil partner. Moving crypto between your own wallets is not a disposal.

Do I need to report if I have losses?

Losses are not taxable but should still be reported in your Self Assessment so they can be carried forward and offset against future gains — losses have to be claimed within four years.

Does CryptoLens actually file my return?

No. CryptoLens produces a fully calculated HMRC-compliant CGT report as PDF and CSV, with Section 104 pooling, same-day and 30-day rules applied. You (or your accountant) use it to complete your Self Assessment.

Don't leave your 2025/26 return until January

One missed deadline costs £100 before HMRC even looks at the numbers. Calculate now, file with confidence, and never think about it again until next year.

Start my 2025/26 report

CryptoLens provides information, not tax advice. Check your return with a qualified accountant before filing.