CARF Self-Certification: What Your Exchange Will Ask
Updated 17 October 2026
General information only, not tax advice. We are not HMRC and are not affiliated with it. Check GOV.UK and your platform. Last checked against GOV.UK: 17 October 2026. Anything marked expected should be re-checked; we plan to re-check the CARF pages on 1 December 2026. Examples use made-up figures or GOV.UK's own examples. Do not enter personal identifiers (National Insurance number, UTR, name, date of birth) on this site.
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Short answer: GOV.UK says individual users must give each cryptoasset service provider: full name, date of birth, the address and country where they normally live, and a tax identification number (for UK residents this could be a National Insurance number or UTR; not required if your country doesn't issue one). You must give these details to every provider you use, even if it isn't UK-based. If you give inaccurate details or don't give details to a UK provider, you could get a penalty of up to £300; for non-UK providers it could be higher.
What the self-certificate must contain (IEIM8000440)
HMRC doesn't set a format, but an individual's self-certificate must contain: first and last name, residence address, jurisdictions of tax residence, the TIN for each reportable jurisdiction, and date of birth. It is valid only if signed or positively affirmed by the individual and dated no later than the date of receipt. (Entities and controlling persons have their own lists.)
Timing
HMRC's manual says a self-certificate should be obtained when the relationship starts and before the provider carries out transactions. For users existing at the end of 2025, the provider has until 31 December 2026 (Thursday), and should obtain the certificate before continuing to effect transactions for them. Whether and how a platform will restrict your account if you don't respond is for the platform to say; check its terms.
Staying safe
- Only respond through your platform's official app or website, typed or bookmarked by you; don't follow links in unexpected emails.
- This site never asks for identifiers and you shouldn't enter them here.
FAQ
Do I give the same details to every platform? GOV.UK says yes, to each provider you use.
What if I can't get a tax ID? GOV.UK: not required if you aren't eligible for one.
What we could not verify
Uncertain. These points were not confirmed on the pages read. A re-check of the GOV.UK CARF pages is planned for 1 December 2026.
- Which platforms will send requests, and when: not stated by GOV.UK. Do not rely on a specific platform's timetable.
- The exact contents of each platform's report beyond "user details and a summary of transactions".
- HMRC's online reporting service for platforms is "not live yet" per GOV.UK on 17 October 2026.
- Staking, airdrops, mining and lending income are now covered in crypto income (HMRC manual and GOV.UK read 17 October 2026). Detailed DeFi cases (CRYPTO61000 onwards) and whether platforms report reward income under CARF: not verified.
- Interaction with EU DAC8 and other countries' rules.
- We plan a re-check of the GOV.UK CARF pages on 1 December 2026.
Sources (official)
- GOV.UK (HMRC), Information you need to give to UK cryptoasset service providers (last updated 1 January 2026) — https://www.gov.uk/guidance/information-youll-need-to-give-to-uk-cryptoasset-service-providers (read 17 October 2026)
- GOV.UK (HMRC), IEIM8000470 Self-certificates – time limits — https://www.gov.uk/hmrc-internal-manuals/international-exchange-of-information/ieim8000470 (read 17 October 2026)
- GOV.UK (HMRC), Reporting cryptoasset user and transaction data (last updated 3 June 2026) — https://www.gov.uk/guidance/reporting-cryptoasset-user-and-transaction-data (read 17 October 2026)
- HMRC International Exchange of Information Manual, IEIM8000440 Required content in self-certificates — https://www.gov.uk/hmrc-internal-manuals/international-exchange-of-information/ieim8000440 (read 17 October 2026)
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