Crypto Tax Calculator UK 2026/27 — How to Calculate Capital Gains on Cryptoassets

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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 to Calculate Crypto Capital Gains Tax in the UK

List every disposal in the tax year — each sell, crypto-to-crypto swap, spend and non-exempt gift.
For each disposal, record the GBP market value at the moment of the disposal as the proceeds.
Work out the cost of what you disposed of using HMRC's matching rules in order: same-day acquisitions first, then anything bought in the next 30 days (the "bed and breakfasting" rule), then the Section 104 pooled average cost for everything else held in that token.
Gain on each disposal = proceeds − matched cost − allowable fees. Add all gains and losses together for the year.
Deduct the £3,000 annual exempt amount from the net gain, then apply 18% within your remaining basic rate band and 24% above it.

HMRC does not publish an official crypto tax calculator — you self-assess using these rules and report the figure on your Self Assessment return. The calculator above estimates steps 4–5 once you have your total gain; dedicated crypto tax software can automate the pooling in steps 1–3 across large transaction histories.

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 (across all disposals/swaps) —

      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.

Compare Online Accountants →

Transparency & Methodology

Crypto Capital Gains Tax Calculator

Independent, Open-Source Estimator

An independent calculator applying published HMRC CGT rates deterministically — no AI estimate, no official affiliation.

Last updated: 7 September 2026

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.

Frequently Asked Questions

Do I pay tax when I sell cryptocurrency?

Yes — if your total gains from disposing of cryptoassets in a tax year exceed the £3,000 annual exempt amount, Capital Gains Tax is due at 18% or 24% depending on your income.

Does swapping one crypto for another count as a taxable event?

Yes — HMRC treats exchanging one cryptoasset for a different one as a disposal, the same as selling for GBP, even if you never move funds to a bank account.

When do I need to declare crypto gains?

Through Self Assessment, by 31 January following the end of the tax year in which the disposal happened — there is no 60-day deadline for crypto, unlike UK residential property.

Is there a separate crypto tax rate in the UK?

No — cryptoassets are taxed under the same Capital Gains Tax rules and rates (18%/24%) as shares and other chargeable assets; there is no crypto-specific rate.

How do I calculate crypto capital gains tax in the UK?

For each disposal, take the GBP value at the time of the disposal, subtract the cost of what you disposed of using HMRC's same-day, 30-day and Section 104 pooling rules, and subtract allowable fees. Add all the gains and losses for the year, deduct the £3,000 annual exempt amount, then apply 18% within your remaining basic rate band and 24% above it.

Is there an HMRC crypto tax calculator?

No — HMRC does not provide an official crypto tax calculator. You work out the gain yourself using its cryptoassets manual and report it through Self Assessment. This page gives an estimate, and specialist crypto tax software can automate the share-pooling across large transaction histories.