Crypto Tax CARF Calculator Trending

The Crypto Asset Reporting Framework (CARF) is a new international reporting standard developed by the OECD and adopted by the UK. From 1 January 2026, UK crypto asset service providers must collect and report information about their users' transactions to HMRC, who will exchange this data with other tax authorities. It works in much the same way as the CRS regime already used for bank accounts, and foreign exchanges with UK customers report too, so the platforms sending data include Coinbase UK, Kraken, Crypto.com, Revolut and eToro among others. They have collected the data since 1 January 2026 and send the first reports, covering 2026, to HMRC by 31 May 2027. Penalties for undeclared crypto gains run up to £30,000, with criminal prosecution possible in the worst cases.

Under CARF, reportable transactions include exchanges of crypto for fiat currency, crypto-to-crypto swaps and transfers of crypto assets. The framework requires reporting the total gross proceeds, number of transactions and the type of crypto asset for each user, alongside identity details: name, address, National Insurance number and tax residence. Realised gains and losses, and income such as staking rewards, mining income and airdrops, are all within scope. Stablecoin trades count as disposals even when you swap USDC for USDT, NFT purchases and sales are captured, so is DeFi yield, and wrapping or unwrapping a token such as WBTC is treated as a disposal. HMRC cross-references what it receives against Self Assessment returns, and discrepancies trigger investigations. All of this is separate from your personal obligation to declare gains on your tax return.

This calculator estimates your reporting exposure under CARF based on your transaction history. It summarises which of your trades are reportable, the total gross value that will be reported to HMRC and whether your activity triggers additional due-diligence requirements. In the worked example, 12 crypto-to-fiat sales with gross proceeds of £24,000 and 30 crypto-to-crypto swaps worth £45,000 add up to £69,000 of reportable gross value across 42 transactions. The gross figure is not your tax bill. The CGT liability is a separate calculation based on gains after cost basis.

Capital Gains Tax on crypto in 2026/27 is charged at 18% for basic-rate taxpayers and 24% for higher-rate taxpayers, the rates that have applied to all chargeable assets since 30 October 2024. The Annual Exempt Amount is £3,000, cut from £12,300 in two steps (to £6,000 in April 2023 and £3,000 in April 2024). A higher-rate taxpayer with a £20,000 crypto gain deducts the £3,000 exemption and pays 24% on the balance, which comes to £4,080. Cost is worked out under the Section 104 pooling rules, so you use the average cost across all purchases of the same asset rather than picking a favourable lot. The 30-day rule stops bed-and-breakfasting: if you sell and buy back the same asset within 30 days, the repurchase is matched against the original cost.

Income tax applies to crypto activity that is not a capital gain. Mining income is taxed either as a trading profit (20-45% income tax plus Class 4 NI at 6%, falling to 2% at the top) or as miscellaneous income, depending on the scale of the operation. Staking rewards are miscellaneous income taxed at your marginal rate, so £5k of staking for a 40% taxpayer costs £2k in tax. Airdrops are income only if you received them in return for something or as part of a trade; otherwise nothing is due on receipt, and CGT applies when you sell. NFT royalties count as trading or miscellaneous income, a crypto salary goes through PAYE at its value on receipt, and interest earned through lending protocols such as Aave or Compound is miscellaneous income.

Compliance starts with tracking every transaction since you began. Software such as Koinly, CoinTracking or Recap (the UK-specialised option) costs £50-£250 a year and handles the pooling for you. Calculate CGT and income separately, file through Self Assessment by the 31 January deadline, declare crypto on the capital gains pages or the miscellaneous income pages as appropriate, and pay what is owed. Holding without selling triggers no tax at all. A genuinely lost private key can be claimed as a negligible value disposal, producing a capital loss to set against future gains. Hiding activity is no longer a realistic option now that CARF and DAC8 feed HMRC directly.