Guides · Last reviewed 31 October 2026 · 6-minute read

Crypto losses: how to claim them before the four-year deadline

A crypto loss can cut the tax on your future gains, but only once you have reported it to HMRC, and you have four years from the end of the tax year in which you made it. Many people with losses never claim them.

Why claiming matters, even if you owe nothing now

A loss you report is banked: whatever isn't used against gains in the same year carries forward to later years. A loss you never report is simply gone once the deadline passes.

Say you lost £6,000 in 2024-25 and reported it. In 2026-27 you make a £12,000 gain. Your earlier loss brings the gain down towards the £3,000 tax-free allowance, leaving £3,000 taxable instead of £9,000. For a higher-rate taxpayer paying 24%, that is £720 of tax instead of £2,160. This example is illustrative; your figures depend on your own gains and tax band.

How losses are used

• Same-year losses come off first. A loss is deducted from gains in the same tax year, even if that leaves part of your tax-free allowance unused.
• Earlier losses only bring gains down to the allowance. Losses carried forward are used only on gains above the tax-free allowance, and anything left over carries on to later years.
• Capital losses can't reduce income tax. They work against capital gains only, not your salary or other income.
• No loss on gifts or sales to a spouse or civil partner. Those transfers generally can't create a claimable loss.

The four-year deadline

You can claim a loss up to four years after the end of the tax year in which you made it:

Loss made in tax year	Claim by
2022-23	5 April 2027
2023-24	5 April 2028
2024-25	5 April 2029
2025-26	5 April 2030

If you made losses in 2022-23, a year when many crypto prices fell sharply, the deadline is in a few months.

How to claim

• On your Self Assessment return, in the capital gains pages (SA108), for the year you made the loss.
• Not registered for Self Assessment and never made a gain? You can write to HMRC instead.
• Return for that year already filed and closed? The claim can still be made within the four years; an accountant can help you make it in writing.

Either way, you need the figures: what you paid for the tokens, what you got for them, and the UK matching rules applied across all your wallets and exchanges.

Worthless tokens, lost keys and other special cases

• Tokens that became worthless but you still hold: you can tell HMRC they are now worthless; this is called a negligible value claim. HMRC then treats the tokens as sold and immediately bought back at their worthless value, which turns the fall into a loss you can report. The claim covers your whole holding of that token, and can be made when you report the loss.
• Lost private keys: losing access isn't a sale in itself. If there is no realistic way to recover the tokens, a negligible value claim may be possible.
• Stolen or scammed crypto, and collapsed exchanges: the treatment depends on the facts, so get advice before claiming.
• Futures and similar trading: losses may be treated differently from spot losses, depending on how your futures results are taxed. Check with your accountant.

Prefer to hand it over?

You don't have to work out your losses yourself. Every pack we prepare lists your losses with the deadline for claiming each one, and flags tokens that may qualify for a negligible value claim. You, your own accountant or one of our partner accountants can then make the claims.

Sources

• GOV.UK: Capital Gains Tax, losses
• HMRC Cryptoassets Manual, CRYPTO22500: negligible value
• HMRC Cryptoassets Manual, CRYPTO22400: losing private keys

General information, not tax advice. Your own situation may differ; if you are unsure, speak to an accountant.