Crypto capital losses in the UK — claiming and carrying forward
Quick answer: Crypto capital losses offset gains in the same tax year. Unused losses carry forward to future years. Report losses on SA108 box 13.5. You cannot claim income tax relief for capital losses on personal investments. Lost or stolen crypto may still be a disposal — evidence is essential.
Not every crypto transaction makes money. Losses can reduce your tax bill — but you must claim them correctly and keep evidence.
Calculating a capital loss
Loss = allowable cost (pool) minus disposal proceeds. Selling bitcoin below your pooled average creates a loss even if you still hold other tokens.
Using losses in the tax year
Net losses against net gains. If overall net loss, no CGT due — report the loss on SA108 to preserve carry forward.
Carrying forward
Unused losses roll to future tax years and offset future gains. Keep SA108 submissions as proof.
Lost, stolen or worthless tokens
HMRC may accept negligible value claims or theft disposals with evidence — police reports, exchange confirmations. Complex cases need professional advice.
Tax-loss harvesting caution
Selling to crystallise a loss then rebuying within 30 days triggers bed-and-breakfast matching — the loss may not work as expected. Wait 31 days or buy a different asset.
Frequently asked questions
Can I offset crypto losses against salary?+
No. Capital losses offset capital gains only, not Income Tax on employment.