Last updated on 7 August 2026
Selling Crypto to Pay Tax on Crypto Gains: The HMRC Feedback Loop
Many UK crypto investors end up selling some of their crypto to pay tax on earlier crypto gains, and that’s exactly where the “HMRC feedback loop” begins.
It sounds simple: you make a profit, you owe tax, you sell some coins to pay that tax. But, selling crypto can itself create another taxable event, which means you might owe even more tax next year. This ongoing cycle can easily get out of control if you’re not careful with planning and recordkeeping.
What Is the HMRC Feedback Loop in Selling Crypto?
The “feedback loop” occurs when crypto investors sell assets to pay their tax bills, but those sales trigger new gains or losses that will be taxed in the next tax year.
Let’s look at an example:
- In the 2023–24 tax year, you sell some Bitcoin and make a £10,000 gain.
- You owe Capital Gains Tax (CGT) on that gain, let’s say £1,800 (if you’re a higher-rate taxpayer).
- You don’t have £1,800 in cash, so you sell some Ethereum in 2024–25 to cover the tax bill.
- That sale gives you another £2,000 gain.
- Now you’ll owe tax again next year, even though you only sold to pay the first bill.
That’s the feedback loop.
It’s not illegal or even unusual; it’s just the way UK tax rules treat crypto. Every “disposal” (selling, swapping, or spending crypto) is a taxable event under HMRC’s Capital Gains Tax rules.
Why Selling Crypto Catches Beginners Off Guard?
Many new investors think tax only applies when they withdraw crypto into cash. But that’s not true.
HMRC treats crypto just like shares or property; if you sell or swap it for another asset, it’s a disposal, and any gain or loss is taxable.
This surprises beginners for a few reasons:
- They think “crypto-to-crypto” trades don’t count, but they do.
- They forget to track what they originally paid for their coins (the “cost basis”).
- They don’t plan to pay the tax in cash.
So, when HMRC’s tax deadline comes, they have no cash to pay, and must sell more crypto. And that sale becomes another taxable event.
If you are unsure how HMRC interprets crypto transactions or emerging technologies like DAOs, our deep dive on CARF and DAOs: What It Means for UK-Based Web3 Founders breaks down how international regulations are evolving for UK crypto projects.
How to Break the Loop with Selling Crypto?
Breaking this loop is about planning and recordkeeping. You can’t control market prices, but you can control how you prepare for your tax bill.
1. Keep Accurate Records
Record every transaction, even small ones. You need to know:
- Date of each purchase or sale
- Value in GBP at that time
- Transaction fees
- What you swapped or sold
HMRC expects you to keep these records for at least 5 years after the tax year.
If you use multiple wallets or exchanges, record everything in one place. Tools like ALI from Crypto Accountants can automatically read your blockchain data and calculate gains and losses in line with HMRC’s rules.
2. Set Aside Tax Early
If you made a profit during the year, don’t wait until the tax bill arrives. Estimate your tax and set aside cash regularly.
You can do this by:
- Moving a small % of every profit into a savings account.
- Using a crypto tax calculator to estimate CGT in real time.
This way, you will already have funds ready when HMRC’s deadline (31 January for Self Assessment) comes around, and you won’t need to sell more crypto to pay it.
3. Understand the Tax-Year Timing
The UK tax year runs from 6 April to 5 April. Any crypto you sell before 5 April counts for that year’s tax return.
If you know you will owe tax but the market is down, you could wait until the next tax year to sell. This gives you time to plan and may reduce your gain or create a loss that offsets future profits.
If you made big gains in 2023–24 but know prices dropped in early 2024–25, you could realize some losses then. HMRC lets you carry forward unused losses indefinitely to offset future gains.
For those managing complex blockchain setups or smart contracts, it’s worth understanding what an audit covers; see our article on Smart Contract Audits: What Blockchain Reviews Really Check for a detailed overview.
4. Don’t Ignore Losses
Losses can actually help you. You can claim them to reduce future tax bills, but only if you report them.
If you had crypto losses in the 2021–22 tax year, you have until 5 April 2026 to claim them. Report them through your Self Assessment, and HMRC will allow you to use those losses in future years.
Even small losses matter. They can make a big difference when the market rebounds.
5. Know When to Get Help
If your trading volume is high or you’ve used DeFi, NFTs, or cross-chain bridges, things get complicated fast. You may need a professional accountant who understands crypto taxation.
Crypto tax specialists can:
- Reconstruct your transaction history
- Apply UK-specific tax rules (like share pooling)
- Find allowable losses
- Ensure you don’t overpay HMRC
If you are still wondering whether to hire a professional, see our guide on 5 Real Risks of Skipping a Crypto Tax Accountant. It explains why expert advice can save time, stress, and money.
Avoid These Common Pitfalls
- Overlooking small trades: HMRC can track your crypto activity through exchanges, so every transaction counts.
- Not converting to GBP: All figures must be recorded in pounds, even if the trade was made in another currency or crypto.
- Ignoring transfer fee: These costs affect your actual gains or losses and should be included in your calculations.
- Missing the tax-year deadline: Selling just a few days later could shift your tax liability into the next tax year.
Final Thoughts
The HMRC feedback loop is one of the most common problems for new crypto investors. Selling crypto to pay tax feels simple, but it often creates more tax later.
The solution is planning. Keep accurate records, set aside funds early, and understand how tax years work. And when things get complex, it’s worth seeking professional help.
Staying compliant doesn’t have to be stressful, with the right tools and advice.
Need help with crypto taxes?
Get expert tax advisory support from professionals at Crypto Accountants to simplify your crypto tax life today.
FAQs
Do I really pay tax when swapping one crypto for another?
Yes. HMRC treats crypto-to-crypto swaps as a disposal. You calculate the GBP value at the time of the swap and work out your gain or loss.
What happens if I can’t afford to pay my crypto tax bill?
You can contact HMRC and arrange a payment plan, but don’t ignore it. Selling crypto to pay the bill can cause new taxable gains, so it’s best to plan ahead.
Can I use losses from past years to reduce my tax?
Yes. You can carry forward unused capital losses indefinitely, as long as you reported them to HMRC within four years of the tax year they occurred.
How can I make crypto recordkeeping easier?
Use software that connects to your wallets and exchanges. It automatically tracks transactions, values, and gains in line with HMRC rules.
