Most crypto tax tools were built for the US market and adapted for the UK as an afterthought. HMRC's matching rules, the Section 104 pool, and SA108 compatibility are not the same as IRS Form 8949. Here are the five tools that actually handle UK reporting correctly.
What to look for in a UK crypto tax tool
Before comparing tools, the three things that matter most for UK users: correct application of HMRC's three matching rules (same-day, 30-day, Section 104 pool); SA108-compatible output; and an honest free tier that lets you verify your gain before paying anything.
Polyconomic
UK-focused. Free to see your gain. Reports from £49/year.
Pros
- +Free to see your full taxable gain — no subscription required to check your position
- +SA108-compatible PDF reports — Standard £49/year, Pro £99/year
- +All three HMRC matching rules applied correctly
- +ETH and BTC wallet import with historical GBP prices
- +Plain English throughout — no jargon
Cons
- −4 live API connections (more via CSV)
- −No mobile app yet
Best for UK investors who want HMRC-correct results without paying to see their own number.
Koinly
Popular globally, with UK HMRC support.
Pros
- +Large exchange integration library
- +Strong DeFi transaction detection
- +Good UI and portfolio view
Cons
- −Free plan shows gains for up to 10,000 transactions but requires a paid plan for tax reports
- −Pricing is subscription-based (typically from ~£49/year)
- −Designed globally — UK HMRC matching is one of many country modes
Good choice for users with complex DeFi activity or many exchanges who are happy to pay annually.
CryptoTaxCalculator
Australian-origin tool with solid UK support.
Pros
- +Very strong DeFi and on-chain transaction support
- +Clear disposal categorisation
- +Active development
Cons
- −Subscription required to generate reports
- −Not UK-specific — HMRC rules are one supported jurisdiction among many
- −Pricing scales with transaction count
Worth considering for heavy DeFi users with complex on-chain history.
Blockpit
Austrian company with European and UK coverage.
Pros
- +Good exchange integrations
- +Clear audit trail
- +Supports multiple European tax regimes
Cons
- −Built primarily for European (not UK-specific) tax rules
- −Subscription-based
- −UI and support are less UK-focused
A reasonable option, particularly if you have European assets or holdings outside the UK.
CoinTracker
Well-known, primarily US-focused with UK support.
Pros
- +Large user base
- +Good portfolio tracking
- +Well-established
Cons
- −Built for US tax forms — UK is secondary
- −Higher price point
- −Less familiar with HMRC-specific nuances
Better suited to US taxpayers. UK users may find the HMRC output less polished.
Frequently asked questions
Does it matter which tool I use as long as I get the right gain figure?
Yes — because the only way to know the gain is right is if the tool applies HMRC's matching rules correctly. A tool that uses FIFO instead of the Section 104 pool will give you a different (and wrong) number. Always verify that the tool you use is explicitly applying same-day, 30-day, and Section 104 matching.
Can I use a US crypto tax tool for UK reporting?
Not reliably. US tools are built around IRS Form 8949 and typically use FIFO or specific identification — neither of which is correct for HMRC. If a US tool supports UK as a secondary mode, verify independently that the matching rules are being applied before trusting the output.
Do I need to pay before I know my gain?
With most tools, yes. With Polyconomic, no — you can see your full taxable gain for free before deciding whether to buy the SA108-compatible report. This matters because many people turn out to be below the £3,000 allowance and owe nothing.
What happens if the tool I used last year gets the matching rules wrong?
If you filed using incorrect figures, you may have underpaid or overpaid tax. You can amend a Self Assessment return within 12 months of the filing deadline. For older returns, you would need to write to HMRC. Acting proactively is always better than waiting for HMRC to identify the discrepancy.
Do I need a different tool for DeFi and NFTs?
Some tools handle DeFi better than others. CryptoTaxCalculator is widely regarded as having the strongest DeFi transaction detection. Polyconomic handles standard exchange trading, staking, and ETH/BTC wallet imports well. For very complex DeFi history, choose a tool with explicit DeFi support or use a specialist accountant.
How do I switch tools if I used a different one last year?
Most tools allow you to import your full history from scratch. The key issue is ensuring your Section 104 pool is calculated from your first ever purchase — not just from when you start using the new tool. Your historical imports determine your pool average, which affects every future calculation.
Tool information accurate at time of writing. Check each tool's website for current pricing.