The three matching rules, in order
HMRC's Cryptoassets Manual (CRYPTO22200 onwards) applies the share-matching rules of TCGA 1992 to tokens of the same kind:
- Same-day rule: disposals are matched with acquisitions of the same token on the same day, at those coins' cost.
- Bed and breakfast (30-day) rule: what is left is matched with acquisitions in the 30 days after the disposal, earliest first. Selling at a loss and buying back next week does not create a usable loss on the pool's cost — it is matched to the new purchase.
- Section 104 pool: everything else comes from the pool, whose cost is the average of all pooled purchases including allowable fees.
The table under the result labels every matched part with its rule, so you can check the calculation against your own records. The pool quantity and cost after all trades are shown too — that is your starting position for next year.
Exempt amount and rates
The annual exempt amount for individuals is £3,000 from the 2024/25 tax year. It is applied to net gains of the tax year (6 April to 5 April). Losses from earlier years are used only to bring net gains down to the exempt amount, so they are not wasted.
For disposals from 30 October 2024 the CGT rates are 18% within the basic-rate band and 24% above it. The calculator asks how much of the basic-rate band your taxable income leaves unused: that part of the gain is taxed at 18%, the rest at 24%. Disposals before 30 October 2024 were taxed at 10% and 20%; for 2024/25 tax returns with such disposals, adjust by hand.
net gain = gains − losses in the tax year
taxable = net gain − losses brought forward (down to £3,000) − £3,000
CGT = min(taxable, unused basic band) × 18% + rest × 24%Sources and simplifications
HMRC Cryptoassets Manual: gov.uk/hmrc-internal-manuals/cryptoassets-manual/crypto22200. Exempt amount and rates: gov.uk/capital-gains-tax/allowances and gov.uk/capital-gains-tax/rates.
- One token per calculation; each token has its own pool.
- Crypto-to-crypto swaps are disposals: enter the token you give up as a sell at its sterling value and the new one as a buy.
- Trading as a business, non-residence, transfers between spouses and negligible-value claims are not modelled.
- Staking and mining receipts may be income on receipt; they are outside this calculation.
Frequently asked questions
+Can I use FIFO for crypto in the UK?
No. HMRC requires the same-day rule, then the 30-day rule, then the Section 104 pool at average cost. FIFO does not apply.
+What is the crypto CGT allowance in 2025/26?
The annual exempt amount is £3,000 for individuals, the same as in 2024/25.
+What rate do I pay on crypto gains?
18% on the part of the gain that fits in your unused basic-rate band and 24% on the rest, for disposals from 30 October 2024.
+Does the 30-day rule stop me from harvesting a loss?
If you buy the same token back within 30 days, the disposal is matched with that new purchase, so the loss is calculated against the new cost rather than the pool.
+Do I report if my gain is under £3,000?
You may still need to report if your total disposal proceeds were above the reporting threshold or you are in Self Assessment for other reasons. Check gov.uk guidance for the current threshold.
Calculations run entirely in your browser; nothing you type is sent to KOT.CASH. Results are estimates for information only and are not financial, tax or legal advice.