UK Crypto Checklist: 31 January 2027 and 5 April 2027

Updated 17 October 2026

General information only, not tax advice. We are not HMRC and are not affiliated with it. Check GOV.UK. Sources read October 17, 2026. Anything marked expected should be re-checked (re-check planned December 1, 2026). Examples use GOV.UK's own figures or made-up figures. Do not enter personal identifiers (National Insurance number, UTR, name, date of birth) on this site. This page contains no affiliate links.

Short answer: Two cycles overlap. 2025 to 2026 (ended 5 April 2026): GOV.UK says online returns and payment are due by 11:59pm on 31 January 2027 (Sunday), paper returns were due 31 October 2026 (and registering by 5 October 2026 has passed). 2026 to 2027 ends 5 April 2027 (Monday); its return deadlines aren't on the GOV.UK page read and are expected to follow the same pattern (online by 31 January 2028).

A. Before 31 January 2027 (2025-26 return)

Decide whether you must report: the SA108 notes say to complete the summary pages if disposals were worth more than £50,000, gains before losses exceeded £3,000, or you want to claim a loss or election (SA108 boxes).
Compute each disposal in pounds using same-day, 30-day and pool rules (pooling mistakes).
Include crypto income (staking, airdrops in some cases) separately (crypto income).
File the cryptoasset section in the return, in sterling (report gains and losses).
If you want your Self Assessment bill collected through your tax code, GOV.UK says to submit by 11:59pm on 30 December 2026.
Pay any tax by 31 January 2027 (a second date, 31 July, applies if you make payments on account).
Earlier years unpaid? See disclosure service.

B. Before 5 April 2027 (2026-27 tax year end)

Know your £3,000 annual exempt amount and rates (allowance and rates); whether an unused allowance can be carried forward isn't covered by the pages read.
Review realised gains and losses year to date; check same-day and 30-day effects around the date.
Resolve missing cost records (allowable costs).
Lost keys or worthless tokens: consider negligible-value rules before year-end (lost or stolen).
Prepare for platform requests (self-certification; key dates).

FAQ

Is 31 January 2027 for the tax year ending April 2027? No: it is for the year ended 5 April 2026.

Do I need to do anything for CARF? Platforms collect your details; see the CARF guides.

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.

2026 to 2027 return deadlines (31 October 2027 paper, 31 January 2028 online): expected; the GOV.UK page read covers the year ended 5 April 2026 only.
Whether an unused annual exempt amount can be carried forward: not covered by the sources read.
Real time CGT service deadlines: not read.
Platform timelines for self-certification: not stated by GOV.UK.
30 December 2026 for tax-code collection: as stated on the page; eligibility conditions not read.

Sources (official)

GOV.UK, Self Assessment tax returns: Deadlines — https://www.gov.uk/self-assessment-tax-returns/deadlines (read in full October 17, 2026; no review date shown)
HMRC, Capital Gains Tax summary notes, tax year 2025 to 2026 (SA108 Notes 2026, form dated 12/25; GOV.UK page last updated May 13, 2026) — https://assets.publishing.service.gov.uk/media/6a02e5df4fb0713aa63ea77c/SA108-Notes-2026.pdf (cryptoasset boxes and introduction read October 17, 2026)
HMRC CRYPTO22200 — https://www.gov.uk/hmrc-internal-manuals/cryptoassets-manual/crypto22200 (read in full October 17, 2026)

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