How to Report Crypto on Your UK Self Assessment Tax Return

Cryptocurrency is firmly on HMRC’s radar, and if you have made gains, received income, or even swapped one token for another during the tax year, you may have reporting obligations. Here is a plain-English guide to how it works and what you need to do.

Most people assume that reporting crypto to the taxman only applies if you have sold everything and taken out a large profit. The reality is more nuanced. HMRC does not treat cryptocurrency as currency in the legal sense. It treats it as a capital asset, much like shares or property, and that classification shapes almost everything about how you report it.

The two taxes you need to think about are Capital Gains Tax and Income Tax. Which one applies depends on what you actually did with your crypto, not just whether you ended up with more money than you started with.

Capital Gains Tax comes into play whenever you dispose of a crypto asset. HMRC’s definition of a disposal is broader than most people expect. Selling crypto for pounds is a disposal. Exchanging Bitcoin for Ethereum is a disposal. Using crypto to pay for something is a disposal. Even gifting crypto to someone other than a spouse or civil partner counts as a disposal, valued at the market price on the date you gave it away. Each of these events could create a taxable gain or a loss that you need to record.

Income Tax applies in different circumstances. If you mine cryptocurrency, the rewards are treated as trading income or miscellaneous income depending on the scale and organisation of your activity. Staking rewards are generally treated as income at the time you receive them. Airdrops can be income if you received them in return for a service or as part of a promotional scheme, though some airdrops received without conditions may escape income tax at the point of receipt, only to be caught by Capital Gains Tax when you eventually sell.

Working out your gain is done using HMRC’s section 104 pooling rules. Rather than tracking each individual coin you bought and sold, HMRC requires you to maintain a single pool for each type of cryptocurrency you hold. Every time you buy more, the total cost of your pool increases. When you sell, you calculate the proportion of the pool’s total cost that corresponds to the coins you are selling, and the difference between that cost and your sale proceeds is your gain or loss. There are two additional rules that override the pool in specific circumstances: the same-day rule, which applies if you buy and sell the same asset on the same day, and the 30-day rule, which prevents you from selling at a loss and immediately rebuying to crystallise a paper loss for tax purposes.

For the 2024/25 tax year, the annual Capital Gains Tax allowance sits at £3,000. Gains below that threshold do not need to be paid on, though HMRC still asks you to report if your total proceeds from disposals exceeded four times the allowance, which is £12,000. If your gains are within the allowance but your proceeds exceed that threshold, you still need to include the figures in your return. Losses can be carried forward to offset gains in future years, but only if you report them in the year they arose.

The actual reporting happens through your Self Assessment tax return. If you already complete a return each year, you will add your crypto gains using the Capital Gains Summary pages, known as SA108. You will enter the number of disposals you made during the year, the total proceeds, the total allowable costs, any losses brought forward from previous years, and the net gain or loss. If the gain is above the annual allowance, you will pay Capital Gains Tax on the excess at either 18 per cent or 24 per cent depending on whether you are a basic rate or higher rate taxpayer for the year in question.

Crypto income, whether from mining, staking, or qualifying airdrops, goes in a different section of the return. Miscellaneous income has its own box, and if the amounts are significant and your activity looks more like a trade, you may need to complete the self-employment pages instead. The distinction matters because trading income is subject to National Insurance contributions as well as Income Tax, while miscellaneous income is not.

The deadline for filing your online Self Assessment return and paying any tax owed is 31 January following the end of the tax year. So for the 2024/25 tax year, which runs from 6 April 2024 to 5 April 2025, the deadline is 31 January 2026. Miss it and HMRC will charge an automatic £100 penalty, with further daily penalties adding up the longer you leave it.

Record-keeping is arguably the most important practical step, and the one most crypto holders neglect. HMRC expects you to keep records of the date of every transaction, the type and quantity of crypto involved, the value in sterling at the time, and who the other party was. Exchange records, wallet addresses, and transaction IDs all count as supporting evidence. If you have used multiple exchanges, moved assets between wallets, or taken part in DeFi protocols, piecing together an accurate picture can be genuinely difficult. Dedicated crypto tax software such as Koinly, CoinTracker, or TaxBit can aggregate data from multiple sources and produce the HMRC-compatible calculations you need, which most people find far more reliable than doing it by hand.

One thing worth knowing is that HMRC has been actively acquiring data from UK crypto exchanges under its powers to request bulk information. If you think you have flown under the radar by simply not mentioning your crypto, that assumption is increasingly risky. The time to get organised is before you receive a nudge letter, not after.

If you have never completed a Self Assessment return before, you will need to register with HMRC first. You can do this through the government gateway, and you should register by 5 October following the end of the tax year in which you first had taxable crypto activity. For most people, using a qualified accountant with crypto experience is worth considering, particularly if you have multiple years of untangled transactions to work through or if your income from crypto is substantial.

Disclaimer: Cryptocurrency investments are highly volatile and speculative. Their value can rise and fall sharply, and you could lose all of your investment. This article is for informational and educational purposes only and does not constitute financial advice. Always do your own research before making any investment decision.