Which form do crypto gains go on?

The SA108 capital gains summary, filed alongside your main Self Assessment return, in the section for other property, assets and gains, not the listed shares section.

Do crypto-to-crypto swaps count towards what I report?

Yes. Every swap is a disposal at market value, and swap proceeds count towards your total disposal proceeds even when no pounds moved.

When is the deadline?

Online returns and payment are due by 31 January following the end of the tax year. First-time filers must register for Self Assessment by the earlier 5 October deadline.

Does staking income go on the SA108?

No. Staking, mining and payment-in-crypto income is reported as income in the income sections of the return, at its sterling value on receipt. The SA108 takes disposals.

Where crypto goes on your self assessment, box by box

Every January, the same search happens at the same kitchen tables. The return is open, the crypto numbers exist somewhere, and the question is embarrassingly practical, which box. Here is the whole answer, front-loaded, then the detail.

The one-paragraph version. Crypto gains go on the SA108 capital gains summary, in the other property, assets and gains section. HMRC wants totals, disposals count, proceeds, allowable costs, gains, losses, with computations held or attached. Crypto income, staking, mining, salary in tokens, goes in the income parts of the return instead. Online deadline is 31 January after the tax year ends, registration much earlier. Now the parts that catch people.

First, whether you need to report at all

Three separate triggers, any one is enough. Your net gains beat the annual exempt amount, currently £3,000. You want to claim losses, and losses only work once claimed. Or your total proceeds are large despite modest gains, and remember every crypto-to-crypto swap is a disposal, so an active year piles up proceeds fast. Crypto income is its own fourth trigger, reportable even in a year with zero disposals. If genuinely none of these apply, you may have nothing to file for crypto, and the full guide covers what counts as a disposal in the first place.

The SA108, what actually gets typed

The form asks for totals, not transaction lists. Number of disposals, total proceeds, total allowable costs, gains before losses, losses in the year. The real work is that those totals only come out right if every disposal was matched under the right rule in the right order, same day, thirty day, then the section 104 pool, which is the app’s whole job. TaxHash’s SA108 helper presents each computed figure against the specific box number on the current form, verified against the form itself, so filing becomes transcription. The manual’s filing section shows it.

Income is the separate universe. Staking, mining, payment in tokens, reported as income at sterling value on receipt, and that value becomes your acquisition cost later, so nothing gets taxed twice by accident. The app’s income report keeps the two universes apart for you.

The deadlines, and the trap inside them

Online filing and payment, 31 January after the tax year ends, so the year ended 5 April 2026 files by 31 January 2027. The trap is registration. First-time filers must register for Self Assessment by 5 October after the tax year, and registration takes days to process, which is the single most common way a January filing becomes a February penalty. Reading this in January, unregistered? Register today, before reading further.

Payments on account are the second trap, first-time filers can owe a year and a half of tax at once, not crypto-specific, but crypto gains are exactly the lumpy kind that triggers it. Know before January, not on the 31st.

What to keep afterwards

HMRC can ask about a return years later, and the record that answers every question is the disposal-level working, what was sold, when, for what, matched against which acquisition under which rule. Download the year’s report suite, the capital gains report, transaction history, working paper, and keep it with your return. The record keeping guide lists the lot. Storage costs nothing, reconstructing five-year-old DeFi history under enquiry pressure costs a great deal.

Not personal tax advice, and edge cases, trading status, DeFi, residency, deserve a human. The vetted professionals handle exactly this, and your reports hand them everything on day one.