How to Report Crypto Gains on a Self Assessment Tax Return (UK Guide)

How to Report Crypto Gains on a Self Assessment Tax Return (UK Guide)
Charlotte Baroukh

Charlotte Baroukh

Tax Expert @ Pie

4 min read

Updated: 28 May 2025

4 min read

Updated: 28 May 2025

Read This First

Cryptocurrency taxation might seem like a maze of confusing rules, but it doesn’t have to be. HMRC has clear guidelines on how crypto assets should be taxed, and following them correctly keeps you on the right side of the taxman. By following HMRC’s guidance, you ensure you pay taxes correctly on your crypto activities.

With Pie.tax‘s crypto transaction import feature, you can automatically calculate your gains without spreadsheet headaches. It’s important to understand the tax perspective HMRC applies to different types of crypto transactions, as this affects your obligations. Or if you’re just here to get to grips with it all, let’s break it down!

What Counts as a Taxable Crypto Event for Capital Gains Tax?

Not every crypto transaction triggers a tax bill. HMRC's tax treatment of crypto asset transactions determines whether you owe tax. HMRC views cryptocurrencies as crypto assets, not currency, which means they’re subject to Capital Gains Tax when you “dispose” of them.

Disposals include selling crypto assets like your Bitcoin for fiat currency (such as pounds), swapping Ethereum for Solana, spending crypto to buy goods and services, or using crypto to buy goods and services. Each of these actions could create a taxable event for capital gains tax purposes.

Gifting crypto to your spouse is tax-free, but giving it to anyone else counts as a disposal at market value. This applies even if you didn’t receive anything in return, and may result in a taxable gain or capital gain that must be reported as part of your crypto capital gains.

Mining or staking rewards are treated differently. These typically count as income when you receive them, not capital gains.

You are required to report crypto capital gains for capital gains tax purposes, ensuring all taxable gain from disposals is accurately declared.

Crypto Income: What You Need to Know

Crypto income isn’t just about selling coins for a profit—there are several ways you might earn money from crypto assets, and each has its own tax implications. In the UK, if you receive crypto income from activities like mining, staking, trading, or even as payment for goods and services, you’re required to report this on your self assessment tax return. Unlike capital gains, these earnings are subject to income tax and must be included as part of your taxable income for the relevant tax year.

The amount of income tax you’ll pay depends on your total income and which tax band you fall into, with rates ranging from 0% up to 45%. It’s crucial to keep detailed records of all your crypto transactions, including the fair market value of any crypto assets received and any associated expenses.

Crypto investors can reduce their taxable income by claiming allowable expenses, such as the cost of mining equipment, electricity, or software used for managing crypto transactions. Make sure to include all relevant crypto income on your assessment tax return to stay compliant and avoid any surprises from HMRC.

How to Report Crypto Gains on Your Self Assessment

First, you’ll need to register for Self Assessment if you haven’t already. The deadline for registration is 5 October following the tax year in which you had taxable gains. If you are self-employed, make sure to access your business tax account before completing your self assessment.

When filling out your tax return, head to the Capital Gains section. You’ll need to complete the capital gains tax summary, typically using the SA108 form, and report each type of cryptocurrency separately if your total disposals exceed £49,200. Before submission, prepare a crypto tax report or tax report to ensure all figures are accurate for HMRC.

For smaller amounts with gains below the annual tax free allowance (also known as the tax free allowance, £6,000 for 2023/24), you can simply tick the box. This indicates you’ve made disposals but don’t need to report them in detail.

You must calculate and report your total capital gains and net capital gains for capital gains tax purposes.

You can file your return online or via paper tax returns. The deadline for online filing is 31 January after the tax year ends, while paper tax returns must be submitted by 31 October.

Keep in mind that the tax year runs from 6 April to 5 April the following year. Considering tax strategies can help optimize your tax outcome.

Calculating Your Crypto Gains Correctly

HMRC requires a specific calculation method for working out crypto gains. You’ll need to match disposals to acquisitions using rules in this order: same-day, bed and breakfast (within 30 days), then the “Section 104” pooling method.

The pooling method treats each cryptocurrency as a pool, averaging the purchase cost of your holdings. When you sell, you use this average cost to calculate your gain or capital loss.

Don’t forget to include allowable costs like transaction fees when working out your gains. These reduce your tax bill, so keep good records and maintain a complete crypto transaction history for accurate calculations!

Record-Keeping and Tax: Staying Compliant

Accurate record-keeping is the backbone of successful crypto tax compliance. Every crypto investor should maintain detailed records of all crypto transactions, including dates, amounts, market values at the time of each transaction, and any calculations used to determine capital gains or losses.

HMRC requires that you keep these records for at least six years, so it’s wise to use reliable methods—whether that’s a well-organized spreadsheet or specialized crypto tax software. 

Tax Forms and Crypto: Which Forms to Use

When it comes to reporting crypto assets on your tax return, using the correct forms is essential for proper tax compliance. The main form for most individuals is the self assessment tax return (SA100), where you’ll declare your overall income, including any crypto income.

Depending on your situation, you might need to include additional forms. For example, if you receive employment income, you’ll use the P60, and if you have trading income from frequent crypto transactions, the SA103 may be required. 

Special Considerations for UK Crypto Traders

If you’re trading crypto frequently, HMRC might consider your activity a financial trade rather than simple investing. In this case, you may be classified as self employed, and your trading profits will be treated as business income.

Mining income is also treated differently. If your mining activity is considered a business, the mining income will be included in your trading profits, subject to income tax and national insurance.

Other types of crypto income, such as airdrops, may be subject to airdrops income tax. Depending on your circumstances, airdrop rewards can be taxed as miscellaneous income at your normal income tax rate. You must pay income tax on these earnings when received.

NFTs (Non-Fungible Tokens) follow the same tax rules as other crypto assets, despite their unique nature. Their disposal is subject to Capital Gains Tax, so you may need to pay capital gains tax when you sell, trade, or otherwise dispose of NFTs.

For those holding crypto in cold wallets or across multiple exchanges, consolidating your transaction history can be challenging. Nevertheless, it’s essential for accurate reporting.

HMRC has been receiving data from major exchanges since 2019. Don’t assume your trading activity is invisible to the tax authorities.

Final Thoughts

Reporting your crypto gains doesn't need to be daunting if you keep good records throughout the year. The key is tracking every transaction and understanding which ones trigger tax events.

With HMRC's increasing focus on cryptocurrency compliance, staying on top of your crypto tax obligations is more important than ever. Penalties for non-compliance can be severe.

Remember that tax rules change regularly, so it's worth checking HMRC's guidance before filing. Alternatively, consult with a tax professional if your situation is complex.

Taking a proactive approach to your crypto tax planning can save you money. It also prevents the stress of scrambling for information at the last minute.

Pie.tax: Simplifying how to report crypto gains on self assessment uk Tax

Tracking crypto transactions across multiple platforms can quickly become overwhelming, even for casual investors. Pie.tax makes this simple by connecting directly to exchanges and automatically calculating your gains.

The UK’s first personal tax app uses HMRC-approved calculation methods to ensure your crypto taxes are accurate. You won’t need to worry about same-day rules or Section 104 pooling – the app handles all this behind the scenes.

When tax season arrives, you’ll have all your figures ready to go, with clear breakdowns of each disposal. Pie.tax generates a comprehensive crypto tax report for your records and HMRC submission, making filling in your Self Assessment straightforward and stress-free.

The app also helps you spot tax-saving opportunities throughout the year, like using your annual exemption or realising losses. This proactive approach could save you hundreds in tax.

If you’d like to see how easy crypto tax reporting can be, take a look at what Pie.tax has to offer.

For users with complex crypto situations, such as DeFi, NFTs, or intricate trading histories, it’s recommended to seek professional tax advice in addition to using the app.

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