Tell HMRC about unpaid crypto tax — voluntary disclosure guide
Quick answer: Use HMRC’s crypto voluntary disclosure service on gov.uk if you have undeclared crypto income or gains. You must calculate tax, interest and penalties for each year — up to 4, 6 or 20 years depending on whether the failure was careless or deliberate. Pay within 30 days of HMRC accepting your offer.
If you should have paid tax on crypto gains or income but did not, HMRC runs a voluntary disclosure route. Coming forward usually means lower penalties than if HMRC finds the gap first.
Who should use this service
Anyone with undeclared UK tax on exchange tokens, NFTs or utility tokens — from selling, swapping, income, mining or staking. If HMRC opens an enquiry first, different rules apply.
How many years to disclose
Reasonable care failure: typically 4 years. Careless failure: up to 6 years. Deliberate evasion: up to 20 years. You must decide which category applies honestly — HMRC will review.
What to calculate
For each year: Capital Gains Tax on disposals, Income Tax on receipts, interest on late tax, and penalties using HMRC’s penalties and interest calculator. Include number of transactions, exchanges used, and whether you used commercial tax software.
After you submit
HMRC sends a payment reference within 15 working days. Pay within 30 days. Keep copies of calculations. If HMRC cannot accept your offer, they may investigate further.
Getting help
Complex histories — especially DeFi — may need an accountant. Start with our record template, CGT worked example, and tax software guide. HMRC helpline: 03000 55 22 94 for disclosure queries.
Frequently asked questions
Will CARF data trigger automatic investigations?+
CARF helps HMRC match data. Voluntary disclosure before contact usually means better penalty treatment.