What to Tell Your Accountant About Crypto and CARF
Updated 17 October 2026
Our own checklist, not HMRC guidance. This is a house checklist we wrote from the HMRC CARF pages listed below. HMRC does not publish or endorse it.
General information, not tax advice. We are not HMRC and are not affiliated with it. Check GOV.UK. Last checked against GOV.UK: 17 October 2026. Anything marked expected should be re-checked. Examples use made-up figures. This page contains no affiliate links. Do not enter personal identifiers (National Insurance number, UTR, name, date of birth) on this site.
Short answer: HMRC says providers collect your details and report your users' details and a summary of transactions, so that your activity can be linked to your tax record. This page is a preparation checklist we built from those pages, not HMRC guidance. It helps you give an accountant the facts they will need.
Tell them
- Every platform or wallet app you used, including non-UK ones: GOV.UK says details must be given to every provider, even outside the UK.
- Which providers asked you for a self-certificate, and the country of tax residence you stated (do not send identifiers by email without a secure channel).
- Transfers to private wallets you made from platforms: providers report these as external-wallet transfers (IEIM8000585).
- Any DeFi, staking or airdrop activity: HMRC's manual says DeFi software is not itself a provider, but income and gains still need reporting by you.
- Gifts, payments in crypto and lost or stolen assets.
- Earlier years you suspect were not reported: HMRC has a disclosure service.
Bring
- Exchange statements and transaction histories for each tax year.
- Wallet addresses you control and transfers between your own accounts.
- Any letters or messages from platforms about data requests.
- Your own notes on how you matched purchases and sales (see pooling pages).
Questions to ask them
- Does my platform data cover the whole tax year, and do the values match my own records?
- How are my pooled costs built?
- Is there anything from earlier years to correct?
What HMRC's pages do not promise
GOV.UK and the manual do not say the platform summary includes gains, cost basis or a tax calculation (see our page on what HMRC receives). Do not rely on it to prepare your return.
Related
SA108 boxes explained · Reconcile before 31 May 2027 · Pooling mistakes · Disclosure service · Checklist for 31 January 2027
FAQ
Do I need an accountant? Not necessarily; this is general information and not advice.
Should I send my National Insurance number or UTR to this site? No, never.
What we could not verify
Uncertain. These points were not confirmed on the pages read. A re-check of the GOV.UK pages is planned for 1 December 2026.
- Whether any accountant professional body or HMRC page lists a recommended document set (none read).
- How HMRC will compare platform data with returns.
- Whether platform summaries show gains or cost (not stated).
Sources (official)
- GOV.UK (HMRC), Information you need to give to UK cryptoasset service providers (published 14 May 2025, last updated 1 January 2026) — https://www.gov.uk/guidance/information-youll-need-to-give-to-uk-cryptoasset-service-providers (read in full 17 October 2026)
- GOV.UK (HMRC), IEIM8000585: Transfers to external wallet addresses — https://www.gov.uk/hmrc-internal-manuals/international-exchange-of-information/ieim8000585 (read in full 17 October 2026)
- GOV.UK (HMRC), IEIM8000160 — https://www.gov.uk/hmrc-internal-manuals/international-exchange-of-information/ieim8000160 (read in full 17 October 2026)
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