UK crypto tax rules are genuinely complicated — and HMRC's own guidance runs to dozens of pages. These are the ten questions investors ask us most often, answered as plainly as possible so you can understand your position without needing a law degree.
The questions HMRC never answers simply enough
Does HMRC know about my crypto?
Almost certainly, if you use UK-regulated exchanges. HMRC has data-sharing agreements with exchanges operating in the UK, including Coinbase, Kraken, and others. They have sent nudge letters to crypto holders since 2019 using exchange data. HMRC also contracts blockchain analytics firms to trace on-chain activity. The assumption that crypto is private or untraceable is outdated and risky.
Do I need to file Self Assessment just because of crypto?
Yes — if your total gains from all assets exceed £3,000, or if your total disposal proceeds from all assets exceed £50,000 in the year, you must complete SA108. You may also need to file if you have crypto income (staking, mining) above the £1,000 miscellaneous income allowance. If none of these apply and you have no other reason to file, you may not need to — but keep records in case.
What happens if I forgot to declare crypto in previous years?
HMRC accepts voluntary disclosures and is demonstrably more lenient with taxpayers who come forward before being contacted. Interest accrues on unpaid tax from the original due date, but penalties for genuine mistakes are typically 0–30% of the unpaid tax for unprompted disclosures, compared to 30–100%+ if HMRC opens an enquiry first. Use HMRC's online disclosure facility or engage a specialist adviser.
Is holding crypto taxable — even if the price has gone up?
No. Holding crypto, regardless of how much it has appreciated, is not a taxable event. Tax only arises when you dispose of it: sell it, swap it, spend it, gift it, or receive it as income. A Bitcoin worth £100,000 that you have never sold has zero tax liability until the moment of disposal.
What is the CGT annual allowance and does it apply to crypto?
The CGT annual exempt amount for 2024/25 is £3,000. It applies to all capital gains in the year — crypto, shares, investment property — not just to crypto. If your total net gains from all sources are below £3,000, no CGT is due. The allowance has fallen significantly from £12,300 in 2022/23, which means many investors who previously owed nothing now owe tax.
Can I offset crypto losses against other capital gains?
Yes. Losses from crypto disposals reduce your total capital gains for the year, which includes gains from shares, investment property, and other assets. If your crypto losses exceed your other gains, the surplus can be carried forward to future years. You must claim the losses on SA108 in the year they arise — they are not automatically recognised.
What tax rate do I pay on crypto gains?
For 2024/25, the CGT rate on crypto is 18% for basic rate taxpayers and 24% for higher or additional rate taxpayers. Your applicable rate depends on your total taxable income plus your gains for the year. If your income plus gains straddles the basic/higher rate boundary, you may pay two different rates on different parts of your gain.
Are crypto-to-crypto swaps really taxable?
Yes — this is one of the most consistently misunderstood rules. HMRC treats every cryptocurrency as a separate asset. Swapping BTC for ETH is a disposal of BTC at market value. The fact that you did not receive GBP is irrelevant. Each swap creates a potential CGT event on the asset being exchanged, and the received asset takes on a new acquisition cost at the market value of the swap.
Can I put crypto in an ISA to protect gains from tax?
No. Crypto cannot currently be held within a UK ISA. All crypto gains are fully subject to CGT with no ISA shelter available. This is different from shares, where ISA protection is available. HMRC has not indicated any plans to change this. Some crypto-linked investment products (such as Bitcoin ETFs) may be ISA-eligible, but those are indirect exposures — not holding crypto directly.
What records do I actually need to keep, and for how long?
For every transaction: the date, the type (trade, transfer, staking reward, etc.), the asset, the quantity, the GBP value at the time of the transaction, fees paid, and the exchange or wallet involved. Keep records for at least 5 years after the 31 January self-assessment filing deadline for the relevant tax year. For assets that remain in your Section 104 pool, records may be relevant indefinitely until you fully dispose of that asset.
Frequently asked questions
Does HMRC distinguish between frequent traders and long-term holders?
HMRC can treat very active crypto trading as a trading business (subject to Income Tax rather than CGT) if the activity has the hallmarks of a trade: frequency, organisation, profit motive, and business-like conduct. In practice, HMRC rarely applies trading status to individual retail investors. Most active retail investors are still taxed under CGT rules.
Do I pay tax on crypto received as payment for freelance work?
Yes. Crypto received as payment for services is treated as employment or self-employment income at the GBP value on the date received. It is taxable as income in the year received, and Income Tax plus National Insurance contributions may apply. When you later sell that crypto, only the gain above the income value declared is subject to CGT.
What is the 30-day bed-and-breakfasting rule and why does it matter?
If you sell an asset and repurchase the same asset within 30 days, the sale is matched against the repurchase rather than your Section 104 pool. This prevents selling to crystallise a gain or loss and immediately rebuying. It is why timing of repurchases around year-end disposals matters significantly in tax planning.
Can HMRC go back more than four years to investigate crypto tax?
Yes — HMRC can go back up to 6 years for careless errors and 20 years for deliberate underreporting. The standard 4-year window only applies to straightforward mistakes. If HMRC believes you deliberately omitted income or gains, their powers to investigate historic years are much broader.
Is there any crypto investment that is exempt from UK tax?
There are no CGT exemptions specifically for crypto. Gains are fully taxable above the £3,000 annual exempt amount. Some structured crypto products (certain bonds or collective investments) may have different tax treatment, but direct crypto holdings have no preferential treatment under current UK tax law.
What is the difference between SA108 and SA100 for crypto reporting?
SA108 is the Capital Gains Summary supplementary page where you report disposal proceeds, costs, and net gains or losses. SA100 is the main tax return where you report income — including staking rewards, mining income, and airdrops. Both may be required in the same year if you have both capital gains and crypto income.
Tool information accurate at time of writing.