Crypto Tax Calculator UK

What this calculator does

It works out the Capital Gains Tax on one disposal of one type of token. You enter what the sale or swap was worth in pounds, the fees, your pool of that token (units and total cost) and any units you bought the same day or in the 30 days after. The calculator matches the disposal in the order HMRC requires, finds the gain, applies the annual exempt amount and shows the tax. It also shows what is left in the pool afterwards for your next disposal.

What counts as a disposal

gov.uk lists selling tokens, exchanging them for a different cryptoasset, using them to pay for goods or services and giving them to another person. Gifts to a spouse, civil partner or charity are excluded. Swapping one token for another is a disposal even though no pounds change hands, so you need the sterling value of what you received.

The matching order

Each type of token you own is grouped into its own pool, with a pooled cost. HMRC's manual sets the order for matching a disposal. First come units bought on the same day. Next come units bought in the 30 days after the disposal, earliest first. Only what is left is taken from the pool at its average cost. Units bought but not matched go into the pool. This is the same approach as for shares.

The pool at average cost

If you hold 10 units that cost £10,000 in total, the pool cost is £1,000 a unit, whatever you paid on each purchase. Selling 5 units uses £5,000 of cost. Include the fees you paid when buying in the pool cost (incidental costs of buying are normally allowable). A fee paid in tokens is itself a small disposal, which this calculator does not model.

The annual exempt amount and the rates

The Capital Gains Tax allowance for individuals is £3,000 for 2026/27 (gov.uk). Gains above it are taxed at 18% within the basic Income Tax band and 24% above it, for gains from 6 April 2026. The same 18% and 24% have applied to disposals since 30 October 2024; before that date the rates were 10% and 20%. The calculator uses 18% and 24% and your taxable income to decide how much of the gain falls in the basic band. Losses on this disposal are set against other gains in the same year.

A worked example

You hold 10 units with a pool cost of £10,000 and sell 5 for £12,000. The pool cost used is £5,000, so the gain is £7,000. After the £3,000 allowance, £4,000 is taxable. With no other income it all falls in the basic band, so the Capital Gains Tax is £720. A higher-rate taxpayer would pay £960 on the same gain.

Income Tax instead of Capital Gains Tax

If you have already paid Income Tax on part of a token's value, for example because you received it as employment earnings, you do not pay Capital Gains Tax on that amount. Mining, staking and airdrop income are not modelled here.

Reporting and records

You report through your Self Assessment return, which has a cryptoasset section from the 2024/25 tax year onwards, completed in pounds, or through the Capital Gains Tax real time service. Exchange reports are not tax calculations and do not track pooled costs, so keep your own records of each transaction. NFTs are separately identifiable and are not pooled.

What this calculator does not cover

It handles one token and one disposal at a time. It does not model fees paid in tokens, NFTs, income from mining or staking, brought-forward losses, or disposals before 30 October 2024. It is an estimate, not advice.