Record keeping, what HMRC expects you to hold

Checked against app build 2026-08-26-01-41 on 2026-08-26.

HMRC’s guidance is blunt, the burden of keeping cryptoasset records sits with you, not with your exchange. Exchanges close, delist, and prune history, and “the exchange deleted it” has never impressed an inspector.

What records does HMRC expect for cryptoassets?

For each transaction, the type of asset, the date, whether it was a buy, sell, swap or transfer, the quantity, the value in pounds at the time, and what wallet or exchange held it.

This is exactly the shape of a gains.tax workspace, which is not a coincidence, the app’s import preview and working paper are built around the records HMRC describes in its cryptoassets manual.

How long do I need to keep crypto records?

For self assessment, at least until HMRC’s enquiry window on that return has closed, and in practice longer.

Late-discovered errors reach back years. Crypto records deserve the long habit anyway, because your 2021 acquisitions price your 2027 disposals under the pooling rules, see the UK rules. Filing dates for the current year are in the deadline countdown.

What is the cheapest way to comply?

Two files per year, exported when you file.

The session file, exported from the app any time, free at every size, is the complete machine-readable record and reopens in the app years later. The working paper is the human-readable one, every disposal with its rule and citation, the document you would hand an accountant or an inspector, see the report family. Export both when you file, store them wherever you store tax papers, done.

What if an exchange I used has already vanished?

Import what you have and let Reconcile flag the gaps.

Missing acquisitions covers the honest ways to handle history you can no longer fetch, including adding an acquisition manually with your best-evidenced date and cost.