When crypto disposals trigger Capital Gains Tax, income vs capital, the £3,000 allowance, record-keeping and HMRC nudge letters explained for UK investors.
Crypto tax in the UK trips people up because the rules feel out of step with how the asset behaves. HMRC does not treat Bitcoin, Ethereum or any other token as money. It treats them as property, the same broad category as shares. That single decision drives almost everything: you are usually in Capital Gains Tax territory, not Income Tax, and a "disposal" happens far more often than most investors realise. Selling for pounds is obvious. Swapping ETH for a stablecoin, paying for a service in crypto, or gifting tokens to a friend are all disposals too, each one a taxable event measured in sterling at the moment it happens.
This guide explains when crypto is taxed as a capital gain versus income, how the share-pooling rules work, what the 2025/26 allowances and rates are, and how to keep records HMRC will accept. It also covers the nudge letters landing on doormats and how to respond if you have gains you never declared.
Almost everyone investing in crypto is on the capital gains side. You buy tokens, hold them, and pay tax on the profit when you dispose of them. The exceptions are where you receive crypto rather than buy it.
Crypto is taxed as income in a narrower set of cases: mining rewards, staking rewards, airdrops received in return for a service or as part of a trade, and crypto received as salary or for freelance work. These are valued in pounds on the day you receive them and taxed under Income Tax at 20%, 40% or 45% depending on your band, sometimes with National Insurance if it amounts to a trade. When you later sell coins you originally received as income, a second, separate Capital Gains Tax calculation kicks in, with the sterling value at receipt becoming your acquisition cost.
If staking or mining income, or crypto-paid freelance work, pushes your overall position into Self Assessment, it stacks on top of any other earnings. Use the multiple-income tax calculator to see how crypto income sits alongside a salary or self-employment, and check your tax code if a PAYE job is already using your personal allowance.
Your gain on a disposal is the sterling proceeds (or market value for a swap or gift) minus the allowable cost of the tokens you disposed of, minus certain costs such as exchange or transaction fees. Add up all your gains and losses across the tax year, subtract the GBP 3,000 annual exempt amount, and the remainder is taxed.
For 2025/26 the rates are 18% on gains that fall within your remaining basic-rate band and 24% on gains above the basic-rate threshold. To work out which applies, stack your taxable income first: the personal allowance covers the first GBP 12,570 of income, the basic-rate band runs to GBP 50,270, then 40% to GBP 125,140 and 45% above. Your crypto gains sit on top of your income, so a higher earner pays 24% on all their crypto gain, while a basic-rate taxpayer pays 18% until the gain fills the band and 24% on the rest.
The GBP 3,000 annual exempt amount is per person and cannot be carried forward, so if you do not use it in a year it is lost. Spouses and civil partners each have their own GBP 3,000, and transfers between them are tax-neutral, so couples can sometimes share holdings to use both allowances and both basic-rate bands. For a wider walkthrough of CGT across shares, property and crypto, see our capital gains tax guide.
This is where crypto tax gets genuinely technical, and where most spreadsheets go wrong. You will rarely have bought all your Bitcoin at one price, so HMRC uses pooling and matching rules to decide the cost of the coins you dispose of.
| Scenario | How the cost is matched |
|---|---|
| Sell 1 BTC, bought BTC earlier the same day | Same-day rule: use that day's purchase cost |
| Sell 1 BTC, rebuy BTC within 30 days | 30-day rule: matched to the rebuy, not the pool |
| Sell 1 BTC, no recent buys | Section 104 pool: use the average pooled cost |
| Swap ETH for USDC | Disposal of ETH at market value; USDC enters its own pool |
Because the pool spans every wallet and exchange you use, you cannot calculate crypto CGT one platform at a time. You need a consolidated record of every acquisition and disposal, in sterling, across the whole of your activity.
HMRC expects you to keep records for each transaction even though exchanges may not. For every event you should capture the type of token, the date, whether it was a buy, sell, swap, spend, or income receipt, the quantity, the value in pounds at that moment, the running pool position, and any fees. Bank statements and wallet addresses should be retained too.
In practice most active investors use crypto tax software that pulls transactions from exchanges and wallets via API or CSV, applies the pooling and matching rules, and produces a CGT report and income summary. Treat its output as a starting point, not gospel: missing wallets, internal transfers misread as disposals, and unpriced obscure tokens are common errors that change the numbers. Keep the underlying exports so you can defend any figure. The closer you get to the MTD era, the more valuable continuous, digital record-keeping becomes, and our MTD for sole traders guide explains the direction of travel.
You report capital gains on the capital gains summary (SA108) pages of your Self Assessment return. You generally need to report if your total disposal proceeds exceed GBP 50,000 in the year, or your taxable gains exceed the GBP 3,000 allowance, or you simply want to register a loss. Crypto income from staking, mining or payment goes on the relevant income pages instead.
The deadlines are the familiar Self Assessment ones: register by 5 October after the tax year if you are new to it, file online by 31 January, and pay any tax due by the same date. Unlike UK residential property, crypto disposals do not have a separate 60-day reporting window, so everything funnels through the annual return.
The investors who get caught out are not the ones with big gains. They are the ones who swapped tokens dozens of times, never priced each swap in pounds, and assumed only cashing out to a bank account counted. Every swap is a disposal.
HMRC has sent large batches of nudge letters to people it believes hold crypto, prompting them to check whether they have reported correctly. These are not assessments, but they are a clear signal that HMRC has data linking you to an exchange. From 2026 the OECD Cryptoasset Reporting Framework will require exchanges to report holdings and transactions to tax authorities automatically, widening visibility further.
If you receive a letter, or simply realise you have undeclared gains from previous years, do not wait. You can correct the current year through your return and use HMRC's Crypto Disclosure facility for earlier years. Coming forward voluntarily nearly always means lower penalties than HMRC discovering it first, and interest accrues the longer it is left. Where the numbers are large or the history is messy, take professional advice before disclosing.
Take someone earning GBP 35,000 from employment who actively trades crypto. Over the year their disposals (after applying pooling) net out to a GBP 9,000 gain, and they also received GBP 600 of staking rewards.
Staking income: GBP 600, taxed as income at 20% = GBP 120 (it also adds GBP 600 to total income for band purposes).
Capital gain: GBP 9,000 minus the GBP 3,000 annual exempt amount = GBP 6,000 taxable gain.
Band check: income of GBP 35,600 leaves roughly GBP 14,670 of basic-rate band before the GBP 50,270 threshold, so the whole GBP 6,000 gain fits inside it.
CGT: GBP 6,000 at 18% = GBP 1,080.
Total crypto tax: GBP 120 income tax plus GBP 1,080 CGT = GBP 1,200. Had this person been a higher-rate taxpayer, the gain would have been taxed at 24% instead. To model how income and gains interact in your own situation, run the figures through the dividends and investment tax calculator, which handles the band-stacking the same way.
Thinking only cashing out counts. Token-to-token swaps and spending crypto are disposals. Investors who traded heavily on-chain often have far more taxable events than they expect.
Calculating per-exchange. The Section 104 pool spans every wallet and platform. Working one exchange at a time produces the wrong cost basis.
Forgetting income events. Staking and mining rewards are income at receipt, separate from the later CGT calculation. Missing the income receipt understates tax and corrupts your cost basis.
Ignoring losses. Unreported losses are wasted relief. Claim them within four years and carry them forward against future gains.
Assuming small holdings are invisible. Exchanges already share data with HMRC, and the 2026 reporting framework expands it. The nudge letters are evidence HMRC is already matching names to wallets.
Capital Gains Tax for 2025/26: the GBP 3,000 annual exempt amount, property, shares and crypto rates, the 60-day property reporting rule and how CGT fits into Self Assessment.
UK landlord tax guide: the SA105 property pages, the 20% finance-cost credit on mortgage interest, allowable expenses, the £1,000 property allowance, joint ownership and MTD.
How UK dividend income is taxed in 2025/26: the £500 dividend allowance, 8.75/33.75/39.35% rates, director-shareholder salary-plus-dividends planning and Self Assessment.
How UK residents declare foreign income on SA106: arising vs remittance basis, foreign tax credit relief, overseas rent, dividends and pensions, plus MTD for Income Tax.
Side hustle tax in the UK: the £1,000 trading allowance, when to register, combining a job with self-employment, payments on account and MTD for Income Tax explained.
CIS subcontractor tax explained: reclaiming 20% and 30% deductions through Self Assessment, refunds, gross payment status, verification, allowable expenses and MTD.
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