What counts as a disposal
A disposal for Capital Gains Tax is much broader than selling for cash. HMRC describes it as “a broad concept” which includes selling tokens for money, exchanging tokens for a different type of token, using tokens to pay for goods or services, and giving tokens away to another person (CRYPTO22100). Transfers to a spouse or civil partner are outside it, as are gifts to charity, subject to the tainted-donation rules.
What is not a disposal: moving tokens between addresses you beneficially control. HMRC is explicit that there is no disposal where “the individual retains beneficial ownership of the tokens throughout the transaction”. That extends to mixers and tumblers where the same type of token comes back — but if token A goes in and token B comes out, that is a disposal.
The three matching rules, in order
When you dispose of a cryptoasset, it is matched against acquisitions in a strict statutory order. This is the part that most software gets approximately right and most self-preparers get wrong.
- Same-day rule (s.105 TCGA 1992). All tokens of that type acquired on the same day as the disposal are treated as a single acquisition and matched first.
- 30-day rule (s.106A TCGA 1992). Tokens of that type acquired in the 30 days after the disposal do not go into the section 104 pool — they are matched against the earlier disposal instead. This is the bed-and-breakfasting rule, and it applies whether or not you intended to bed and breakfast anything.
- Section 104 pool (s.104 TCGA 1992). Anything left over is matched against the pool, which holds all your other acquisitions of that token at their aggregate cost. One pool per token type — bitcoin, ether and every other token each have their own.
Note that NFTs are excluded entirely. Being separately identifiable, they are not pooled and no matching rules apply to them.
A worked example
The clearest way to see why this matters is with numbers. Assume the following bitcoin transactions.
| Date | Transaction | Amount | Consideration |
|---|---|---|---|
| 10 January 2024 | Buy | 2 BTC | £60,000 |
| 5 March 2025 | Buy | 1 BTC | £45,000 |
| 12 June 2026 | Sell | 1 BTC | £70,000 |
| 20 June 2026 | Buy | 0.5 BTC | £34,000 |
Before the disposal, the section 104 pool holds 3 BTC at a cost of £105,000, an average of £35,000 per BTC. Now match the 12 June disposal:
- Same day: no acquisitions on 12 June. Nothing matched here.
- Within 30 days after: the 0.5 BTC bought on 20 June falls inside the window, so 0.5 BTC of the disposal is matched against it. Proceeds attributable: £35,000. Cost: £34,000. Gain: £1,000.
- From the pool: the remaining 0.5 BTC comes out of the pool at £35,000 per BTC. Proceeds attributable: £35,000. Cost: £17,500. Gain: £17,500.
Total chargeable gain: £18,500. After the annual exempt amount of £3,000 for 2026/27, £15,500 is taxable — £3,720 at the higher rate of 24%.
The pool afterwards holds 2.5 BTC at £87,500. The 0.5 BTC bought on 20 June never enters it, because it was consumed by the matching.
Now look at what a naive calculation produces. Ignore the 30-day rule, average everything, and you get a gain of £35,000 rather than £18,500 — and a tax bill roughly £3,960 higher. In this example the rule works in the taxpayer’s favour, because the repurchase was at a high price. In a falling market it works against you, disallowing a loss you thought you had crystallised. Either way, applying it is not optional.
Allowable costs — what you can and cannot deduct
| Cost | Allowable? |
|---|---|
| The original sterling consideration paid | Yes — s.38(1)(a) TCGA 1992 |
| Exchange fees on buying and on selling tokens | Yes |
| Transaction fees required to get the transaction onto the ledger | Yes |
| Professional costs of drawing up the contract; valuation and apportionment costs needed to compute the gain | Yes |
| Fees on depositing or withdrawing fiat currency | No |
| Mining electricity and equipment | No — not incurred wholly and exclusively on acquiring the tokens |
| Costs already relieved against income | No — no double relief |
| The cost of a token-to-token swap fee | Apportioned between the two sides on a just and reasonable basis under s.52(4); HMRC accepts 50/50 |
One trap worth naming: paying a fee in tokens is itself a disposal of those tokens at market value (CRYPTO22280). HMRC will accept a simplified approach that omits the fee’s market value from consideration provided only the fee’s allowable cost is included, so that the computed gain remains correct.
Rates, allowances and reporting for 2026/27
- Annual exempt amount: £3,000 for individuals; £1,500 for most trustees.
- Rates: 18% within the basic rate band, 24% above it. Trustees and personal representatives pay 24%. These rates have applied to disposals since 30 October 2024.
- Reporting thresholds. You must complete the capital gains pages if you disposed of chargeable assets worth more than £50,000, or your gains before losses exceeded £3,000. The £50,000 proceeds test bites even where there is no tax to pay — which catches a very large number of high-churn crypto traders who assume no gain means no filing.
- SA108 has a dedicated cryptoassets section at boxes 14 to 22 — number of disposals, proceeds, allowable costs, gains before losses, losses, claims and elections, real-time return gains and losses, and tax already paid on those. Note that boxes 13.1 to 13.8 are the separate residential property and carried interest section — entering cryptoasset gains there is a common and expensive mis-filing.
- Real-time CGT service: report by 31 December in the tax year after the gain and pay by 31 January. UK residents only, and if you are already in Self Assessment you must still include the disposal on your return.
Frequently asked questions
Is swapping one coin for another taxable if I never touched cash?
Yes. Exchanging tokens for a different type of token is expressly a disposal. This is the most common reason people who have never withdrawn a penny to their bank account nonetheless have a significant chargeable gain.
Does the 30-day rule apply if I did not mean to bed and breakfast?
Yes. It is mechanical. Any acquisition of the same token within 30 days after a disposal is matched to that disposal regardless of intention — which is why active traders trip it constantly without realising.
Do I have to file if I made no profit?
Possibly. The £50,000 disposal-proceeds test is independent of whether you made a gain. If your total disposals exceeded £50,000 in the year, the capital gains pages are required even at break-even.
Can I use different pools for coins on different exchanges?
No. Pooling is by token type, not by location. All your bitcoin sits in one pool whether it is on three exchanges, a hardware wallet or a paper backup.
What if I have losses from earlier years?
Allowable losses are set against gains of the same year first, and any excess carries forward indefinitely. Losses from earlier years have to have been notified to HMRC to be usable, so unclaimed historic losses are worth reviewing — particularly where a collapsed token or platform is involved.
This page is general guidance on UK tax law as at 9 August 2026 and is not advice for any particular person or situation. Tax treatment depends on your individual circumstances and may change. Where we quote HMRC’s internal manuals, note that those manuals are guidance prepared for HMRC staff, are not law, and do not bind HMRC in an individual case. Please take advice before acting. Reviewed by the TaxDigit crypto tax team · Last reviewed 9 August 2026. Updated August 2026.
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TaxDigit is a UK crypto tax accountant practice. Chartered certified accountants preparing capital gains computations, section 104 pools and Self Assessment returns for cryptocurrency investors.
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