CryptoTax UK · Guide
CARF 2026: the new crypto reporting rules that change everything
From 1 January 2026, the global Cryptoasset Reporting Framework comes into force in the UK. Every crypto exchange and service provider you use must collect your personal details and report your transactions directly to HMRC. If you have unreported crypto gains, the window to come forward quietly is closing fast. Educational only — not tax advice.
Calculate and declare before CARF kicks in →What is CARF?
The Cryptoasset Reporting Framework is an OECD-developed international standard for automatic exchange of crypto transaction data between tax authorities. The UK adopted CARF into law, requiring all UK-regulated cryptoasset service providers — exchanges, brokers, and some wallet providers — to collect, verify and report user data to HMRC from 1 January 2026 onwards.
What data is being reported to HMRC
Under CARF, service providers must report: your full name and address, tax identification number (National Insurance number), date of birth, and a full summary of your crypto transactions — including all purchases, sales, exchanges, and transfers, with GBP values. This data is reported annually, giving HMRC a detailed picture of every user's activity across all participating platforms.
What this means if you haven't declared past gains
HMRC already had data from exchanges going back to 2019. CARF makes that data flow automatic, comprehensive, and international. If you have gains from the 2020/21, 2021/22, 2022/23 or 2023/24 tax years that you haven't declared, HMRC now has — or will very soon have — the information to identify you. Voluntary disclosure before you receive an HMRC letter results in significantly lower penalties.
The £300 fine for non-compliance with CARF
Separately from tax obligations, HMRC can fine crypto users £300 for failing to provide accurate personal details to cryptoasset service providers as required by CARF. From January 2026, every platform you use will require you to confirm your tax residency and National Insurance number. Failing to provide this information is itself a compliance breach.
What you should do right now
First, ensure all your crypto accounts are updated with accurate personal details — name, address, National Insurance number. Second, review whether you have undeclared gains from previous tax years and consider using HMRC's Cryptoasset Disclosure Service. Third, ensure your 2024/25 Self Assessment (due 31 January 2026) includes all your crypto activity — this is the first year HMRC's return has a dedicated crypto section.
Frequently asked questions
Does CARF apply to overseas exchanges I use?
CARF is being adopted by over 50 countries simultaneously. If you use an exchange based in a CARF-participating country, they will report your data to their local tax authority, who then shares it with HMRC. The days of non-UK exchanges being invisible to HMRC are ending rapidly.
What about decentralised exchanges and self-custody wallets?
CARF currently focuses on centralised service providers. Pure DEX activity and self-custody wallet transactions are not directly captured by CARF — but HMRC can still trace on-chain activity using blockchain analytics. The obligation to self-report remains regardless of whether a platform reports.
I've always declared everything — does CARF affect me?
If you have been declaring your crypto gains and income accurately, CARF changes nothing for you in practice. The data HMRC receives will simply confirm what you already reported. You may receive additional verification requests from exchanges, but your tax position is unaffected.
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Calculate and declare before CARF kicks in →Educational guidance only. CryptoTax UK is not a regulated tax adviser and the information above does not constitute tax, legal or financial advice. Always confirm your specific position with HMRC or a qualified accountant before filing.