Crypto CGT and Share Pooling in the UK: 2026/27 Guide

Quick answer

In the UK, you pay Capital Gains Tax when you dispose of crypto - selling, swapping token for token, spending it, or gifting it to anyone except a spouse. HMRC pools each token's total cost (the Section 104 pool) and you pay tax on the gain above the GBP 3,000 allowance, at 18% within the basic-rate band and 24% above it for 2026/27.

What counts as a disposal

The single biggest mistake UK crypto investors make is assuming tax only bites when GBP lands back in their bank account. It does not. HMRC treats the following as disposals for Capital Gains Tax:

• Selling crypto for GBP or any other fiat currency.
• Swapping one token for another, for example Bitcoin for Ethereum or any token for a stablecoin.
• Using crypto to pay for goods or services.
• Giving crypto away to anyone other than your spouse or civil partner.

Each disposal is valued at the token's market value in GBP on the day it happens. The gain is that proceeds figure minus the allowable cost taken from your pool, minus allowable fees. Transfers between your own wallets are not disposals, and gifts to a spouse or civil partner transfer at no gain and no loss.

How share pooling works

HMRC does not let you choose which specific coins you sold. Instead, identical tokens of the same type are grouped into a single pool, formally the Section 104 holding. The pool records two running totals: the total quantity of that token and the total allowable cost in GBP.

When you buy more of a token, both totals rise. When you dispose of some, you remove a proportional slice of the pooled cost based on the fraction of the holding sold. This gives an average cost per unit rather than a first-in, first-out or last-in, first-out approach.

A worked pooling example

Suppose you make three Bitcoin purchases and then one sale. The pool builds up like this.

When you sell 0.6 BTC, the average pooled cost is GBP 45,000 divided by 1.5, which is GBP 30,000 per BTC. So 0.6 BTC carries an allowable cost of GBP 18,000. The gain is GBP 24,000 of proceeds minus GBP 18,000 of cost, which is a GBP 6,000 gain. The pool then drops to 0.9 BTC with GBP 27,000 of remaining cost.

You can model the headline gain and the tax due with our

, then adjust for your own income band.

The same-day and 30-day rules

Before you ever touch the Section 104 pool, two ordering rules can override it. They exist to stop investors from selling to bank a loss or reset a gain and then buying straight back.

1. Same-day rule. Any tokens of the same type acquired on the same day as a disposal are matched against that disposal first, regardless of the pool.
2. 30-day rule (bed and breakfasting). Tokens reacquired in the 30 days after a disposal are matched next, on a first-in, first-out basis, again ahead of the pool.
3. Section 104 pool. Only what is left over after the first two steps is matched against the main pool average.

In practice the 30-day rule means you cannot crystallise a loss for tax and immediately rebuy the same token to keep your position. If you do, the loss is deferred into the reacquired tokens rather than realised. To genuinely harvest a loss you generally need to stay out of that token for more than 30 days, or repurchase a different asset.

Allowance, rates and bands for 2026/27

For the 2026/27 tax year the Annual Exempt Amount is GBP 3,000. That is the total tax-free slice of net gains across all your assets combined, not a separate crypto allowance. Net your gains against any capital losses first, then apply the GBP 3,000.

Capital Gains Tax on whatever remains is charged at:

• 18% to the extent the gain falls within your remaining basic-rate band, and
• 24% on any portion above the basic-rate threshold.

To find the split, stack your taxable gains on top of your taxable income. The basic-rate band runs to a gross income figure of GBP 50,270, so the room left below that point is taxed at 18% and anything above at 24%. Business Asset Disposal Relief sits at 18% but is unlikely to apply to ordinary crypto holdings.

Because the rate depends on your other earnings, it is worth checking your income position first with our

. If a salary sacrifice or pension contribution lowers your taxable income, more of your gain may fall into the 18% band.

When crypto is income, not capital

Not every crypto event is a capital matter. HMRC generally treats the following as income, taxed under Income Tax and sometimes National Insurance:

• Mining rewards, where the GBP value on receipt is taxable as income.
• Staking rewards, again valued in GBP when received.
• Airdrops received in return for doing something, such as promoting a project.
• Being paid in crypto by an employer or client.

The GBP value at the moment you receive these tokens is the income figure, and it also becomes the cost basis that enters your pool. So you can be taxed twice over time: once as income on receipt, and later as a capital gain on the growth in value when you dispose. If you receive crypto through self-employment, model the position with our

.

Reporting and record-keeping

You report crypto gains on the Capital Gains summary of a Self Assessment return. You generally need to file where your taxable gains exceed the Annual Exempt Amount, where total disposal proceeds breach the reporting threshold, or where you want to register a loss to carry forward.

Capital losses are set first against gains in the same year, and any unused balance can be carried forward indefinitely provided you report it, usually within four years of the relevant tax year. Losses cannot normally reduce income. For a token that has become genuinely worthless, a negligible value claim can let you treat it as disposed of for a loss.

Records are not optional. For every transaction keep:

• The date and type of transaction.
• The token type and quantity.
• The GBP value at the time, even for token-to-token swaps.
• The fees paid, which are usually allowable costs.
• Wallet and exchange statements as supporting evidence.

UK exchanges and many overseas platforms now share customer data with HMRC, so the days of crypto being invisible are over. If you cannot evidence your pooled cost, HMRC may estimate your gain in a way that does not favour you.

Common mistakes to avoid

• Ignoring swaps. Token-to-token trades are disposals. This is the most common error and can create large hidden gains.
• Forgetting the pool. Using the price of one specific lot rather than the average pooled cost will give the wrong gain.
• Bed and breakfasting by accident. Rebuying within 30 days defers a loss you thought you had banked.
• Mixing income and capital. Staking and mining rewards are income on receipt and capital on later disposal; treat both stages.
• No records. Without a transaction history you cannot prove cost, fees or losses.

Bottom line

UK crypto tax is built on two ideas: every disposal is a taxable event, and identical tokens are pooled at average cost. Net your gains against losses, use the GBP 3,000 Annual Exempt Amount for 2026/27, and apply 18% within your basic-rate band and 24% above it. Watch the same-day and 30-day rules, separate income events from capital ones, and keep meticulous records. Start by running your numbers through the

and checking your income band, then keep this guide to hand at filing time. This article is general information, not personal tax advice; for complex positions, consult a qualified adviser or gov.uk.