UK crypto tax calculations, simplified.

BlockBooks is a UK-focused crypto tax service. We turn your wallet/exchange activity into HMRC-ready calculations and working papers (SA108 Capital Gains summary and supporting schedules). We handle fungible tokens, NFTs, DEX/DeFi, airdrops, forks, and more.

UK individuals, founders, and SMEs with crypto activity who need accurate Capital Gains and income calculations for Self Assessment. We can also collaborate directly with your accountant.

We prepare the crypto computations and SA108 working papers. You (or your accountant) file your return. If you need a filing partner, we can coordinate.

Most major exchanges (via CSV or API), EVM chains (by address), Bitcoin, Solana, and popular DeFi protocols/DEXs/bridges. If we haven’t seen a venue, we’ll still reconcile it—just provide exports and addresses.

By volume/complexity (venues used, on-chain activity, DeFi/NFT coverage, years in scope) and any cleanup from missing records. Share your data and we’ll quote before work starts.

Typically: (1) wallet addresses and/or CSV exports from exchanges; (2) a list of accounts used; (3) your tax year(s); and (4) any prior-year balances. If you’ve used DeFi/NFTs, tell us the protocols/marketplaces.

We apply HMRC’s share-pooling rules (section 104) and the same-day/30-day matching rules to fungible tokens, and treat NFTs individually (no pooling). We convert each transaction to GBP at the correct time and factor allowable costs and fees where eligible.

Selling for GBP, swapping one token for another, spending tokens on goods/services, or gifting to someone other than a spouse/civil partner are disposals. Moving coins between your own wallets (no change of ownership) isn’t a disposal.

For individuals, the CGT rates are 18% (basic rate band) and 24% (higher/additional rates). The annual exempt amount (CGT allowance) is £3,000. (Residential property has distinct rules.)

Yes. Swapping (e.g., ETH→BTC) is a disposal for CGT. We compute a gain/loss on the token you give up, and set the GBP cost basis for the token you receive.

Fees directly linked to acquiring or disposing of tokens are normally allowable costs. If a fee is paid in tokens, HMRC treats that as a small disposal of the fee token and an allowable cost of the main transaction.

Airdrops may be income if received in return for, or in expectation of, a service; otherwise usually no income on receipt, but CGT applies on disposal. New tokens from a hard fork usually have no income on receipt; CGT applies when you dispose of them.

Rewards are typically miscellaneous income when received (unless part of a trade). Separately, some DeFi transactions can themselves trigger CGT disposals if beneficial ownership/control of the tokens passes to a platform or borrower. We review the protocol terms to classify correctly.

They can, depending on whether beneficial ownership/control transfers (e.g., platform can deal freely with your tokens). If it does, HMRC treats it as a disposal at that point; if not, generally no disposal. Details depend on the protocol mechanics.

Each NFT is a separately identifiable asset (no pooling). Disposal of an NFT is normally subject to CGT; income tax can arise if you trade/deal in NFTs as a business.

You may be able to claim a negligible value loss (or make a disposal at market value) if you can show the asset became of negligible value while you owned it. HMRC sets conditions; claims are tied to the relevant section 104 pool for fungible tokens.

Losses are claimed on your return (SA108) or by writing to HMRC if you don’t file a return. You generally have 4 years from the end of the tax year in which the loss arose to claim.

Transfers to a spouse/civil partner are generally no gain/no loss for CGT. Gifts to charity are often exempt from CGT (subject to rules).

You must file if you have CGT to pay, or if your total disposal proceeds exceed £50,000 in the tax year (even if gains are covered by the allowance). If you have taxable income from crypto (e.g., staking), you may also need to file.

UK tax year runs 6 Apr–5 Apr. Online Self Assessment filing and payment are due 31 January following the tax year (e.g., 2024/25 returns are due 31 Jan 2026). Use SA108 for Capital Gains.

Keep dates, amounts, token types/units, GBP values, fees, wallet/exchange IDs, and transaction hashes. HMRC expects accurate records; individuals should keep tax records at least 22 months after the end of the tax year (longer is sensible for crypto).

Yes. As a UK accountancy/tax service we must complete Anti-Money Laundering (AML) checks before work starts. That means verifying your identity and risk under the Money Laundering Regulations.

We’ll ask for a government-issued photo ID and recent proof of address. For higher-risk or complex cases we may request source-of-funds/crypto evidence (e.g., exchange statements or on-chain history).

These checks are a soft identity verification (not a credit check). Information is used only for compliance and stored securely; records are typically retained for up to 5 years after our engagement ends, as required by regulation. If we cannot complete AML/KYC, we can’t proceed with the engagement.

No. We do not take on engagements where the transaction history includes mixers/tumblers or other techniques intended to disguise provenance (e.g., coin-mixing services, peel chains, deliberate chain-hopping/bridging to hide source, or sanctioned privacy protocols). Our AML duties require a clear, end-to-end audit trail from funding source to disposal.

If we detect obfuscation during onboarding or analysis, we will decline or disengage. Please only proceed if you can provide transparent, verifiable histories (exchanges, wallets, on-chain). If you’re unsure whether a past transaction counts as obfuscation, check with us before sharing data.

From 1 January 2026, UK crypto service providers must collect and report user and transaction data to HMRC under the OECD Crypto-Asset Reporting Framework (CARF), with first reports due 31 May 2027 for 2026. HMRC can also request data directly.

We work from read-only materials (CSV, public addresses, or read-only API keys on request). We never take custody of assets. Outputs include full audit trails so your figures are defensible.