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What Counts as a Taxable Crypto Disposal
HMRC treats each of the following as a disposal that can trigger Capital Gains Tax:
- Selling cryptoassets for GBP or another currency
- Exchanging one cryptoasset for a different one (e.g. BTC → ETH)
- Using cryptoassets to pay for goods or services
- Giving cryptoassets away (except to a spouse, civil partner, or charity)
This means a portfolio that never touched a bank account can still generate a CGT bill from token-to-token swaps alone — a common source of underpayment when people assume only cashing out to GBP counts.
Reporting crypto gains
Unlike UK residential property, crypto gains don't have a 60-day reporting rule — they're declared through your normal Self Assessment tax return, due by 31 January following the end of the tax year (or via HMRC's real-time CGT service if you prefer to pay sooner).
How this calculator works — Formulas & Method
Source: gov.uk/capital-gains-tax/rates, gov.uk/guidance/check-if-you-need-to-pay-tax-when-you-sell-cryptoassets · Deterministic calculation — no AI, no arbitrary estimation
Constants used
| Constant | Value | Source |
|---|---|---|
| Annual exempt amount | £3,000 | gov.uk/capital-gains-tax/rates, 2026/27 |
| Basic rate band upper limit | £50,270 taxable income | gov.uk Income Tax rates 2026/27 |
| CGT basic / higher rate | 18% / 24% | gov.uk/capital-gains-tax/rates |
| Taxable disposal events | Sell, swap, spend, gift (excl. spouse/charity) | gov.uk crypto assets guidance |
| Reporting deadline | 31 January via Self Assessment (no 60-day rule) | gov.uk crypto assets guidance |
Formulas
taxable_gain = max(0, total_gain − £3,000)
— Rate band —
basic_band_remaining = max(0, £50,270 − other_taxable_income)
at_18pct = min(taxable_gain, basic_band_remaining)
at_24pct = taxable_gain − at_18pct
cgt = at_18pct × 18% + at_24pct × 24%
Deterministic calculation based on official 2026/27 bands. Assumes you've already correctly identified each disposal/swap event and its GBP value at the time; always confirm your own position with HMRC or a qualified adviser.
Get It Filed Correctly, Not Just Estimated
This calculator gives an estimate — actually reporting and paying it correctly is a separate step with its own deadline and paperwork.
- Every swap counts as a disposal: trading one cryptoasset for another is a taxable event under HMRC rules, not just cashing out to GBP — many people under-report without realising it. Crypto gains are declared via Self Assessment, due 31 January, not a 60-day deadline.
- Multiple disposals in one tax year: ordering and timing disposals across the 5/6 April boundary can materially change what you owe.
- Inherited or gifted assets: your acquisition cost for CGT purposes isn't always what you think — get the base cost confirmed.
- Business Asset Disposal Relief: can cut your rate to 18% on qualifying gains, but eligibility rules are strict.
A fixed-fee online accountant can handle the return and your wider Self Assessment together.
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Methodology & Sources
Figures are public HMRC rates. For your exact position, use gov.uk/capital-gains-tax.
Not Tax or Legal Advice
Information only. Consult the Chartered Institute of Taxation or an adviser via the FCA Register.
Open Source
Formulas are public. Inspect on GitHub.