When a disposal has to be reported
For an individual, the usual tests are practical. You report if your chargeable gains for the tax year are above the £3,000 annual exempt amount. You also report if the total disposal proceeds of chargeable assets are above £50,000, even when the gains themselves are covered by the exempt amount. You report if you want an allowable loss to be on the record. Having no tax to pay is not the same test as having nothing to declare.
Cryptoassets sit with your other chargeable assets for those thresholds. A share disposal and a token disposal in the same year are not two separate allowances. There is one annual exempt amount.
Self Assessment
The main return is the SA100. Capital gains go on the SA108 supplementary pages. From the 2024/25 tax year the return has carried a cryptoasset section, so token disposals are not folded into the boxes for listed shares. Use the notes that come with the form for the year you are filing. The notes are the authority for which box takes which number. Published commentary on the form has been consistent on two habits that cause rejections and wrong tax:
- Enter gains and losses separately. Do not net them yourself and type only the difference.
- Do not subtract the £3,000 annual exempt amount yourself before you type the gains. The calculation applies the exempt amount.
Losses brought forward from earlier years are not the same figure as losses made this year. They have their own place on the form, and they are used down towards the exempt amount rather than through it. Anything still unused is carried on again.
Income from rewards, mining or airdrops does not go in the capital gains pages. It belongs with the income pages that match the nature of the receipt: employment pages if it was earnings, the relevant self-employment pages if it was a trade, or the miscellaneous income section if that is the right character. A complete return can need both the SA108 cryptoasset section and an income entry.
Dates that matter
| Step | Usual timing |
|---|---|
| Tax year ends | 5 April |
| Register for Self Assessment if you have not filed before and need to | 5 October after the end of the tax year |
| Online return | 31 January after the end of the tax year |
| Pay the Capital Gains Tax due for that year | 31 January after the end of the tax year |
| Paper return, if you use one | 31 October after the end of the tax year |
| Real-time Capital Gains Tax service, where you are not in Self Assessment | Report by 31 December after the end of the tax year |
For the year that ended on 5 April 2026, the online filing date is 31 January 2027, and a person who needed to register and had never filed had a 5 October 2026 registration date. For the year that ends on 5 April 2027, the online filing date is 31 January 2028 and the new-filer registration date is 5 October 2027. A late online return attracts an initial penalty, with further penalties if the delay continues. Paying late adds interest. These notes are not a penalty calculator.
If you are already in Self Assessment for another reason, the cryptoasset entries go on that return even when the amounts feel small. Leaving them off because “it was only a few swaps” is a common way to be wrong.
The Cryptoasset Reporting Framework
From 1 January 2026, UK cryptoasset service providers collect customer identity information, which can include name, address and National Insurance number, and transaction information. The first reports, covering the 2026 calendar year, are due to HMRC by 31 May 2027. The framework is international. Information can also arrive from overseas platforms through the exchange of information, so an account that is not with a UK brand is not outside the design.
CARF is a reporting regime for platforms. It does not replace the individual’s Self Assessment, it does not compute the section 104 pool, and it does not distinguish, by itself, income from gain. A platform report and a tax return can both be true and still look different if one of them uses a different valuation or misses a wallet that never touched that platform. Your own record is what reconciles them.
If earlier years were not reported and should have been, HMRC has a route for disclosing unpaid tax on cryptoassets. Coming forward is treated differently from waiting to be written to. Nothing on this site is a disclosure service. The starting point is the current GOV.UK guidance, not a template downloaded from a forum.
What we will not pretend
Opsigamytensor does not file, does not hold agent credentials, and does not ask for your Government Gateway details. An email to [email protected] is a letter to an editorial desk. Do not send seed phrases, private keys, full wallet exports or identity documents. We do not need them to answer a question about how a rule is framed, and we do not want them.
See also Self Assessment tax returns and Capital Gains Tax on GOV.UK.
