Every crypto tax tool I tried got my DeFi activity wrong — phantom gains on bridges, LP positions taxed as transfers, and no way to verify how a number was calculated. So I built ChainTax.
Route-by-route audit completed April 2026 — auth, payments, concurrency.
Tax engine, classifiers, pricing, API routes.
Same-day, 30-day B&B, S104 pooling. Split-year CGT auto-computed for 2024/25.
Pay per tax year. 14-day refund. Secure payment via Stripe.
The most popular crypto tax tools were built in the US for IRS reporting. They default to FIFO cost basis, treat bridges as disposals, sort LP positions as transfers, and generate generic reports that don't map to SA108. When they added “UK support,” they bolted on Section 104 as an option and called it done.
Wrong cost basis method
FIFO is the default in most tools. HMRC requires Section 104 pooled average cost. Using the wrong method changes every gain calculation.
DeFi mistakes
Bridges taxed as disposals. LP deposits ignored. Staking rewards missing. Each error cascades through your Section 104 pools.
No audit trail
A report that says you owe £14,000 with no explanation of how it got there. Your accountant can't verify it. HMRC can't trace it.
Not a US tool with UK settings. A UK tax engine, built from scratch.
33 protocol-specific classifiers identify LP positions, bridges, staking, and swaps by decoding contract interactions — not guessing from token flows. Every result has a confidence rating.
Every disposal shows exactly how the gain was calculated: which HMRC matching rule was applied (same-day, B&B, or Section 104), the pool snapshot before and after, the price source, and the confidence level. Nothing is a black box.
The 2024/25 tax year has two CGT rate regimes split at 30 October 2024. ChainTax automatically splits disposals at the boundary, computes Box 51, and fills SA108 boxes 13.1 through 13.8.
Built exclusively for HMRC from day one. Section 104 is the only cost basis method. Same-day and bed & breakfast rules are applied in the correct priority order. No FIFO defaults. No multi-jurisdiction compromises.
ChainTax Ltdis registered in Northern Ireland (NI739302). I'm a UK crypto investor — I built ChainTax because I needed accurate tax reports for my own DeFi activity across multiple chains and protocols, and couldn't find a tool that got it right.
The engine handles exchange trades and complex DeFi in one unified calculation. Every result is deterministic. Every gain is traceable. The goal is simple: produce tax reports you can understand and your accountant can verify.
The numbers behind the engine.
3,500+
Unit tests
Tax engine, detectors, pricing, API routes
33
Protocol detectors
Uniswap, Aave, Curve, Lido, Yearn, Convex, EigenLayer, Blur, Seaport NFTs, airdrops, and more
5
Chains
Ethereum, Polygon, Arbitrum, Optimism, Base
3
Exchange imports
Coinbase, Binance, Kraken
S104
Native pooling
The matching method HMRC requires
Box 51
Split-year CGT
2024/25 rate change auto-computed
Independent security audit completed April 2026 — route-by-route code review covering auth, data access, payment flows, and concurrency.
You've just read about who built ChainTax and why. The simplest way to decide if it's for you is to scan a wallet free — we'll show you exactly how 200 transactions get sorted.
200 transactions free · From £49 per tax year · No subscriptions ever