How to Declare Crypto Gains to HMRC (UK 2026/27)

UK cryptocurrency gains are subject to Capital Gains Tax (CGT), with each disposal (sale, trade, conversion) being a taxable event. The 2026/27 CGT annual exempt amount is £3,000 — gains above this are taxed at 18% (basic-rate band) or 24% (higher-rate band) for all asset types after the 30 October 2024 changes. You must calculate gains per disposal, total them for the tax year, deduct any losses and the £3,000 allowance, then report on Self Assessment. From 2025, HMRC also has data-sharing arrangements with major crypto exchanges to identify undeclared gains.

This is the framework for 2026/27.

What HMRC treats as a taxable disposal

HMRC’s position: a disposal happens whenever you do anything with crypto that isn’t just holding it. Specifically:

• Selling crypto for GBP (the obvious case).
• Trading one crypto for another (e.g. BTC for ETH).
• Using crypto to pay for goods or services.
• Gifting crypto to anyone other than a spouse / civil partner.
• Receiving crypto airdrops (often treated as miscellaneous income, taxed differently).
• Mining or staking rewards (received as income, then subject to CGT on disposal).
• DeFi yield, liquidity provision, lending — complex; usually treated as income or capital gain depending on circumstances.

Each disposal is calculated separately for CGT.

HMRC’s crypto tax guidance is at cryptoassets-manual.

The basic CGT calculation per disposal

For each disposal:

Gain = (Disposal proceeds) − (Acquisition cost) − (Allowable expenses)

• Disposal proceeds: the GBP value of what you received (cash, other crypto at market value, etc.) at the time of the disposal.
• Acquisition cost: the GBP cost of the crypto you sold/traded.
• Allowable expenses: transaction fees, exchange fees.

A worked example:

• Bought 0.5 BTC in March 2024 for £15,000.
• Sold 0.5 BTC in October 2025 for £18,000.
• Allowable expenses: £100 in trading fees.
• Gain: £18,000 − £15,000 − £100 = £2,900.

You sum gains across all disposals for the tax year, deduct losses, deduct the £3,000 annual allowance, and the result is taxable.

How crypto-to-crypto is treated

A common confusion. UK tax treats crypto-to-crypto trades as:

• A disposal of the asset you’re trading out of (calculate gain/loss on this).
• An acquisition of the asset you’re trading into (new cost basis).

So if you trade £5,000 of BTC for ETH:

• BTC disposal: calculate gain/loss based on what you originally paid for the BTC.
• ETH acquisition: new cost basis is £5,000 (the GBP value of the trade).

This means many crypto traders generate many taxable events without ever cashing out to GBP. The tax bill can be substantial even if their bank account hasn’t seen the gains.

The 30-day rule (Section 104 pooling)

UK CGT rules for crypto use the “Section 104 pool” method, similar to shares. When you have multiple acquisitions of the same crypto:

• All your holdings of that crypto are pooled at an average cost basis.
• Each acquisition adds to the pool at its purchase price.
• Each disposal removes from the pool at the average cost.

The exception is the 30-day rule (also called “bed and breakfasting” rule):

• If you sell crypto and rebuy the same crypto within 30 days, the matching is against the rebuy (not the pool).
• Effectively, you can’t crystallise a loss by selling-and-rebuying within 30 days.

A worked example:

• Bought 1 BTC for £20,000 (pool).
• Bought another 1 BTC for £25,000 (pool, average cost now £22,500).
• Sold 1 BTC for £18,000.
• Loss: £18,000 − £22,500 = −£4,500.

If you rebought 1 BTC within 30 days at £19,000, the £18,000 sale is matched against the £19,000 rebuy:

• Loss: £18,000 − £19,000 = −£1,000.
• The original £22,500 pool average is unchanged.

The £3,000 annual exemption (2026/27)

For 2026/27, the CGT annual exemption is £3,000.

This was £6,000 in 2023/24, £12,300 before that. The exemption has been progressively cut.

Your total gains (across all assets — crypto, shares, property, etc.) minus losses, minus the £3,000 allowance, equals your taxable gains.

If your crypto disposals net to a gain of £8,000 in 2026/27:

• Taxable gain: £8,000 − £3,000 = £5,000.

If you have losses of £2,000 from other crypto trades and gains of £8,000:

• Net gain: £6,000.
• Taxable after allowance: £6,000 − £3,000 = £3,000.

CGT rates (post October 2024)

From 30 October 2024, CGT rates were unified across all asset types:

• 18% if your gain falls within your basic-rate band.
• 24% if your gain falls within higher-rate / additional-rate bands.

The same rates apply to crypto, shares, residential property other than your main home, etc.

A worked example:

• You earn £40,000 salary.
• Crypto gain (after allowance): £5,000.
• Personal allowance + basic-rate band: £50,270 limit.
• Your income + gain = £45,000 — fully within basic-rate band.
• CGT: £5,000 × 18% = £900.

If your salary were £60,000:

• Basic-rate band already exhausted by salary.
• £5,000 gain falls in higher-rate band.
• CGT: £5,000 × 24% = £1,200.

How to declare on Self Assessment

You report crypto gains in the Capital Gains supplementary page (SA108) of your Self Assessment:

• Date and description of each disposal.
• Disposal proceeds.
• Acquisition cost.
• Allowable expenses.
• Resulting gain or loss.

You don’t need to enter each individual trade if your records are good — you can submit a summary with supporting calculations.

You must also declare:

• Number of disposals in the year.
• Total disposal value (gross, before gains calculation).

Even if your gains are below the £3,000 allowance, you may need to file if your total disposals exceed £50,000 in the year. The reporting threshold is separate from the tax threshold.

When you don’t need to file

You don’t need to register for Self Assessment if:

• Total gains in the year are below £3,000 (annual exemption).
• AND total proceeds (the gross value of all your disposals) is below £50,000.

If either threshold is crossed, you must file.

What about losses?

Crypto losses can be claimed:

• Against gains in the same year: automatically.
• Carried forward to future years: must be claimed within 4 years of the tax year the loss arose.
• “Negligible value claim” for crypto that’s become worthless: HMRC allows you to treat the crypto as effectively sold for £0, creating a loss.

Claiming losses on Self Assessment is straightforward — declare them on SA108 with the relevant tax year.

Crypto-to-crypto trading is taxing

A common gotcha. Active crypto traders making frequent trades generate many taxable events. Calculating gains across hundreds or thousands of trades is non-trivial.

Tools that help:

• Specialist crypto tax software (Koinly, CoinTracker, Recap, Accointing) — import exchange data, generate tax reports.
• Spreadsheets for low-volume traders.
• Specialist crypto accountants for high-volume or complex cases.

The cost of crypto tax software is typically £49–£250/year depending on transaction volume — usually much less than the tax owed.

The £100,000+ disposal reporting

If you have a high-value crypto disposal:

• Above £50,000 of disposal proceeds (gross), you must file even if below allowance.
• The post-disposal date, declared on SA108.

When mining and staking become taxable

Mining and staking are typically treated as:

• Income at the time you receive the reward (taxed at your marginal income tax rate).
• CGT applies when you later sell the mined/staked crypto, on any gain from the value at receipt.

So a £500 reward received from mining is income tax (£100 at 20% basic rate, say). If that crypto is later sold for £700, you have an £200 capital gain on top.

The details vary depending on the nature of the activity — HMRC has specific guidance on staking, DeFi, NFTs, etc.

Internal links

• Do I pay tax on dividends from shares UK?
• How do I file a self assessment tax return for the first time?
• What is the personal allowance and how does it work?

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This guide is information, not regulated financial advice. Crypto tax is complex and changing — speak to a qualified UK tax adviser for material gains or unusual activities like DeFi, staking, or NFT trading.