If you have been putting off understanding UK crypto tax because it seems complicated, you are not alone — but the consequences of getting it wrong are real. These ten facts cover the majority of what most UK investors actually need to know.
What changed in 2024/25 that you need to know
The CGT annual exempt amount fell to £3,000 for 2024/25 — down from £6,000 in 2023/24 and £12,300 in 2022/23. This single change has pushed hundreds of thousands of investors into a reporting obligation for the first time. If you had gains of £4,000 last year and assumed no tax was due because “nothing had changed”, you likely have a filing requirement you are not aware of.
The ten things you need to understand
The annual CGT allowance is £3,000 — and it has not been lower since the 1980s
For 2024/25 and 2025/26, gains below £3,000 across all your capital assets are not taxed. This covers crypto, shares, investment property, and everything else. The drop from £12,300 to £3,000 over two years is dramatic — do not assume your liability is the same as previous years without recalculating.
Every crypto-to-crypto swap is a taxable event
This is the most common source of underreported gains in the UK. Every swap — BTC to ETH, USDT to SOL, anything to anything — is a disposal of the first asset at market value. The fact that you never saw GBP does not change anything. If you traded actively on a DEX or swapped between coins frequently, your total disposal count may be in the hundreds without you realising it.
Staking rewards are income, not capital gains — and they go on a different form
Staking rewards are taxed as miscellaneous income at the GBP value on the date received. They go on SA100 (income), not SA108 (capital gains). Putting them in the wrong place means underpaying income tax and getting your CGT figures wrong. There is also a £1,000 miscellaneous income allowance — if your total crypto income is below this, it may not need to be reported.
HMRC requires a specific calculation method — not FIFO
UK law requires same-day matching first, then 30-day look-ahead, then the Section 104 average cost pool. This is completely different from FIFO (used in the US, Australia, and many other countries). Using the wrong method produces incorrect figures — sometimes in your favour, sometimes not — and does not constitute a valid return.
HMRC receives data from exchanges operating in the UK
Under information-sharing agreements, UK-regulated exchanges provide customer data to HMRC. This includes transaction histories, balances, and identity information. HMRC has been sending nudge letters to crypto holders since 2019 using this data. Do not assume that because a transaction happened abroad or on a non-UK exchange it is invisible.
You may need to file even if you owe no tax
If your total disposal proceeds (the total you received from all sales and swaps, not the gain) exceed £50,000 in the year, you must file SA108 — even if your net gain is below £3,000. For active traders and anyone who sold a large position, this threshold is easier to hit than it sounds.
Losses only count if you claim them
A year of crypto losses is only useful if you report those losses on SA108. Unreported losses cannot be carried forward. You have 4 years from the end of the tax year to make the claim — after that, they are permanently forfeit. Many investors who had heavy losses in 2022 have already lost the opportunity to claim them for carry-forward if they did not report in 2022/23.
Transferring assets to a spouse before disposal can double your effective allowance
Transfers between spouses are treated as no-gain, no-loss — your spouse takes on your cost basis. They can then dispose of the asset using their own £3,000 annual exempt amount. Two people, two allowances, one asset — this is a legitimate and widely used strategy. The 30-day rule does not apply to spouse transfers.
Your Section 104 pool starts from your first ever purchase
The average cost pool for each asset accumulates from the very first time you ever bought it — not from when you started using a particular tool or the start of the most recent tax year. If you bought Bitcoin in 2017 but only imported data from 2021, every calculation made from that incomplete pool is wrong. Missing historical data is not just a past-year problem.
The filing and payment deadline is 31 January 2026 for 2024/25
The online Self Assessment deadline for 2024/25 (tax year ending 5 April 2025) is 31 January 2026. Late filing triggers an automatic £100 penalty even if no tax is due. Interest accrues on unpaid tax from 1 February. If you are not already registered for Self Assessment and have a reporting obligation, you needed to register by 5 October 2025.
Frequently asked questions
I have never filed Self Assessment before. How do I register?
Register on the HMRC website using your Government Gateway account. If you do not have one, you can create it during registration. You must register by 5 October in the year after the tax year — so for 2024/25 (ending 5 April 2025), the registration deadline was 5 October 2025. If you have missed this, register immediately and contact HMRC to explain.
My gains are below £3,000 but my total proceeds are above £50,000. Do I need to file?
Yes. The £50,000 proceeds threshold is separate from the £3,000 gains threshold. If total proceeds from all disposals in the year exceed £50,000, SA108 must be filed even if your net gain is zero or a loss. This is commonly missed by people who had large positions that they sold at breakeven.
What CGT rate applies if my income puts me in the basic rate band for some gains and higher rate for others?
Your gains are stacked on top of your income. The part of your gains that, when added to your income, falls within the basic rate band is taxed at 18%. The part that falls above the basic rate threshold is taxed at 24%. You may effectively pay two different rates on the same year's gains.
Can I give crypto to my children to use their CGT allowance?
Gifts to children are treated as a disposal at market value — triggering a CGT calculation for you. The child takes on the market value as their acquisition cost. Children do have their own CGT allowance (£3,000) but there are anti-avoidance rules (the settlements legislation) that can attribute gains back to parents in some circumstances. Seek advice before implementing this.
Does the £3,000 CGT allowance reset on 6 April regardless of how much I have used?
Yes. The annual exempt amount is a fresh £3,000 each tax year, starting 6 April. Unused allowance cannot be carried forward to future years. This is why tax year-end timing of disposals can matter significantly for those with gains close to the threshold.
I moved from the UK to another country mid-year. Am I still liable for UK CGT on crypto disposals?
Possibly — this depends on your residence status and the timing of disposals relative to your departure. UK CGT applies to UK residents. If you became non-UK resident during the year, disposals after your departure date may not be subject to UK CGT (though they may be subject to tax in the new country). The exact position depends on your specific circumstances and professional advice is strongly recommended.
Tool information accurate at time of writing.