HMRC will soon have direct access to your crypto transactions. For the first time, they’ll be able to see exactly what you’ve been buying, selling and swapping across exchanges and wallets. As a result, now is the time to strongly consider filing a crypto tax return if you haven’t already done so. 

In this article, we will explain HMRCs increased access as well as the UK’s crypto tax rules. We will also cover how to use crypto tax software to easily calculate your crypto taxes so you are ready to submit everything on time each year.

If you prefer, we've created a video guide below:
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HMRC Crypto Crackdown‍

HMRC has, until now, relied on self-reporting. In essence, they’d only see your crypto transactions if you declared them or if they specifically requested your records from exchanges.

But from January 2026, they will have direct access to your transaction data from all the major crypto platforms.

What Does This Mean for You? ‍

This is a game changer for many UK crypto investors - no more hiding in the hope they won’t notice.

If you’ve got unreported gains from previous years, or you’re not sure if you’ve been calculating things correctly, now’s the time to act.

HMRC Crypto Tax Rules in 2025‍

First off, is crypto taxable in the UK? Yes, it is.

So, how much is crypto tax in the UK? This depends on the nature of your crypto transactions and your income bracket. Here’s a simple breakdown:

In the UK, there' s primarily 2 taxes you could owe on crypto:

• Capital Gains Tax (CGT) applies when you sell, swap, or spend crypto, so even swapping one coin for another can trigger a taxable event.
• Income Tax applies to any earnings you make through mining, staking or DeFi - similar to earning interest or dividends from stocks.
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What HMRC Expects From You‍

Quite simple so far but here’s where it gets tricky:

HMRC expects you to keep detailed records of every transaction, including the:

• Dates
• Amounts
• Market value in GBP (on the date of the transaction)
• Fees you paid when making the transaction

Manually tracking all of this across multiple wallets and exchanges is where most people go wrong. This is where Koinly comes in.

What is Koinly and How Does It Work?‍

In short, Koinly helps you easily calculate your gains/losses and prepare your crypto tax filings:

1 - It connects directly to your exchanges, wallets and blockchains via API or CSV upload.

2 - It pulls in all your transaction data and matches transfers between your own wallets.

3 - It calculates your gains/losses and formats everything into a crypto tax report according to UK tax rules. It even uses HMRC's share pooling method to calculate cost basis so that your numbers line up with what HMRC expects.‍

How To Calculate Crypto Taxes using Koinly

Step 1 – Sign Up‍

First, go to Koinly here.

Then, create your account, set your country to the UK, and choose GBP as your base currency.
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Step 2 - Add Wallets & Exchanges‍

Add each exchange and wallet you use. There’s 2 methods for this:‍

Set up API connections - This is recommended as they’re automatic, updating in real time. 
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Upload CSV Files - Such as those you’ve exported from platforms/wallets. These may be needed for older data or unsupported platforms
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Once you’ve added your wallets and exchanges, Koinly will begin pulling the data.‍

Step 3 - Check Your Transactions‍

Once done importing, Koinly will flag missing cost basis or other gaps. Work through these, often it’s just a deposit from another one of your wallets that needs linking.
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This is important because missing data can make your gains look bigger than they are.‍

Step 4 – Review Tax Summary‍

Once everything’s reconciled, head to the Tax Reports tab.

You’ll see your total disposals, capital gains, and any crypto income.

You can also drill down to see exactly how each figure was calculated.
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Step 5 – Download Your UK Tax Report‍

Koinly produces a UK-specific Capital Gains Summary that you can select and later use to fill in your Self Assessment form.

You will need to click View Plans in order to purchase any given report for your selected year.

Once purchased, you you can simply click Download.

Koinly even generates the HMRC SA108 form, which you can upload directly via HMRC’s online system.

Having done this for various clients, we recommend attaching the Koinly crypto tax report. Since it’s built around HMRCs requirements, it provides mountains of data and avoids unnecessary back and forths.‍

Step 6 – Backdate if Needed‍

If you realise you’ve missed reporting gains in previous years, don’t wait for HMRC to contact you.

With Koinly, you can export the transactions from past years. 

Of course, with the CSV method, you’ll need to upload the previous years’ data. 

If you opted for the simpler API method, then these will already have been imported for you.

From there, simply change the tax year in question and download your transactions.

This is crucial if you wish to disclose previous gains before HMRC contacts you.
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Voluntary Disclosure

Doing this now, before you are asked to is called a voluntary disclosure. We recommend this if you have any undisclosed gains.

Now that you have your Koinly report for the gains in question, either use HMRC’s Worldwide Disclosure Facility to declare them proactively or simply ask your crypto tax accountant to help you with this - recently we’ve been helping various clients do just that, so please fill in the form here if you’d like our help with this.

This is what we recommend because coming forward before they’ve opened an investigation often results in:

• Reduced penalties, and
• Lowering the amount of interest you owe on any outstanding tax amounts (the longer you wait, the more interest you’ll owe)

In addition, remember, from January 2026, HMRC will have direct access to your past transactions.

Key Takeaways:

1 - Get all your transaction data in one place — Koinly is perfect for this.‍

2 - Reconcile every transaction — missing data may inflate your gains.‍

3 - Generate HMRC-ready reports — and submit them on time.‍

4 - Backdate if needed — voluntary disclosure is always better than receiving an HMRC letter.‍

5 - Stay up-to-date — keep your Koinly account linked so future years are easy.

Next Steps

HMRC’s new powers aren’t something to panic over - but they are a reason to take action now before they come into effect.

If you want to take control of your crypto taxes while avoiding nasty surprises, we’ve added a direct link to Koinly here. Full transparency, that link also supports our work here. Big thanks if you use it!

We hope this guide has helped explain how to handle your UK crypto taxes in 2025 and beyond. If you want our help with any of this, please complete the short form on this page.