UK Crypto CGT Calculator — 2025/26
Free calculator using the post-October 2024 CGT rates (18% basic, 24% higher) and the 2025/26 £3,000 annual exempt amount. For Self-Assessment due 31 January 2027 (tax year 6 April 2025 to 5 April 2026).
UK Crypto CGT Calculator — 2025/26 Tax Year
HMRC treats crypto as a chargeable asset. This calculator uses the 18% / 24% CGT rates that took effect 30 October 2024 and the 2025/26 £3,000 annual allowance.
£3500 taxed at 18% basic + £0 at 24% higher rate. Allowance £3000 deducted first.
UK's share-matching rules (same-day, bed-and-breakfasting 30-day rule, Section 104 pool) make manual calculation nearly impossible once you have more than a few trades. Koinly imports from every major UK exchange and applies the pooling rules automatically.
Generate your HMRC-ready report with Koinly →Methodology & sources
Rates reflect the CGT increase effective 30 October 2024: basic rate 18%, higher rate 24% (previously 10%/20%). Source: GOV.UK Capital Gains Tax rates.
Annual exempt amount for 2025/26: £3,000. Personal allowance £12,570 (frozen through 2027/28). Basic rate band ends at £50,270 combined income.
Not included: Section 104 pool cost basis averaging across multiple buys; same-day and 30-day bed-and-breakfasting rules; losses brought forward; additional rate 45% band (for income > £125,140 — CGT still uses 24% max).
How UK crypto tax works in 2025/26
HMRC treats cryptoassets as a chargeable asset, not currency. The governing document is the Cryptoassets Manual, a detailed internal HMRC guide that has been expanding since 2018.
What triggers a disposal?
- Selling crypto for GBP or any other fiat currency
- Exchanging one crypto for another (this is a disposal of the first, not just a swap)
- Using crypto to pay for goods or services
- Gifting crypto to anyone other than your spouse or civil partner
HMRC considers the disposal value to be the GBP market value at the moment of the event, not the value at some later point.
The CGT rate change on 30 October 2024
The Autumn Budget 2024 aligned crypto CGT rates with residential property CGT. Effective for disposals on or after 30 October 2024:
- Basic rate band: 18% (was 10%)
- Higher rate band: 24% (was 20%)
Which rate applies depends on your total income — the gain stacks on top of your income to determine which rate band it falls in. The basic rate band for 2025/26 ends at £50,270 (personal allowance £12,570 + £37,700 basic band).
Section 104 pooling — the UK's cost basis method
Unlike the US (FIFO/LIFO/HIFO), UK rules mandate a single method: Section 104 pooling. All your holdings of the same cryptoasset sit in one pool with a single average cost. When you sell, the cost basis comes from the pool average.
Example: Alice buys 1 BTC at £20,000 and later buys 1 BTC at £30,000. Her Section 104 pool holds 2 BTC with an average cost of £25,000. If she sells 1 BTC at £40,000, her gain is £40,000 − £25,000 = £15,000.
The 30-day rule (bed-and-breakfasting)
HMRC has two priority rules that override Section 104:
- Same-day rule: sales match first to crypto acquired on the same day.
- 30-day bed-and-breakfasting rule: sales then match to crypto acquired in the following 30 days.
Only after these two rules are exhausted does the Section 104 pool apply. This prevents artificial loss-harvesting where you sell at a loss, immediately rebuy, and claim the loss.
£3,000 annual exempt amount
Each individual has a £3,000 CGT annual exemption for 2025/26 (it was cut from £6,000 in 2023/24 and £12,300 in 2022/23). Gains up to the allowance are tax-free. The allowance cannot be carried forward if unused.
When you must file Self-Assessment
You must file if either:
- Your total taxable gains exceeded £3,000 in the tax year, or
- Your total disposal proceeds exceeded £50,000 even if gains were under the allowance
The £50,000 threshold was lowered from £49,200 × 4 in earlier years. It catches even profitless traders who moved a lot of crypto.
What Koinly and other software handle for you
Section 104 pooling is nearly impossible to do by hand once you have more than a handful of trades across exchanges. Software:
- Imports transactions from 400+ exchanges including Kraken, Coinbase, Bitpanda and UK-specific ones like BitPrime and Luno
- Converts every transaction to GBP at HMRC-acceptable exchange rates
- Applies the same-day, 30-day and Section 104 rules in the correct priority order
- Handles crypto-to-crypto swaps (which are disposals at GBP market value)
- Generates a Self-Assessment-ready CGT summary
Our pick: Koinly is our default recommendation for UK filers. Pricing from £49/year for up to 100 transactions. Free to import and preview — you only pay to export.
Common UK crypto tax mistakes
- Ignoring crypto-to-crypto swaps. A Uniswap trade from ETH to USDC is a disposal of the ETH.
- Treating transfers between your own wallets as sales. They're not — no disposal occurs.
- Missing the same-day / 30-day priority. Software handles this; manually it's a minefield.
- Forgetting staking and DeFi income. Staking rewards are miscellaneous income at GBP market value on receipt (HMRC position since 2022 Cryptoassets Manual update).
- Not claiming losses. Report all losses, even when below the allowance — they carry forward indefinitely to offset future gains.
Timeline for the 2025/26 tax year
- 6 April 2025: 2025/26 tax year starts
- 5 April 2026: 2025/26 tax year ends
- 5 October 2026: deadline to register for Self-Assessment if you have not filed before
- 31 October 2026: paper Self-Assessment deadline
- 31 January 2027: online Self-Assessment deadline and balancing payment due