CryptoTax UK · Guide

How to do your UK crypto tax without an accountant

UK crypto tax accountants typically charge £300–£1,500+ for annual crypto tax work. For most investors, this is unnecessary — if you use the right tools and follow HMRC's rules, you can calculate and file your own crypto taxes accurately. This guide takes you through every step. Educational only — not tax advice.

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Step 1: Gather all your transaction history

Download complete transaction exports from every exchange you have ever used — Coinbase, Binance, Kraken, and any others. Include all years, not just the current tax year. If you use self-custody wallets (Metamask, Ledger, Trezor, Phantom), note all your wallet addresses — you will need them to pull on-chain transaction history. Do not overlook DeFi platforms, NFT marketplaces, or play-to-earn games if relevant.

Step 2: Calculate gains using HMRC's rules

This is where most people struggle with manual spreadsheets. HMRC requires three matching rules to be applied in order: same-day rule (match buys and sells on the same day first), 30-day rule (match sells with acquisitions in the next 30 days), then the Section 104 pool (a weighted average cost pool for all remaining holdings). A UK-specific crypto tax calculator applies all three rules automatically — this is the single biggest time saver.

Step 3: Identify income separately from capital gains

Separate out any crypto you received as income during the year: staking rewards, mining income, airdrops received for services, salary paid in crypto. These are taxed as income at your Income Tax rate — not as capital gains. Report them on the income pages of your Self Assessment, not on the capital gains pages.

Step 4: Complete your Self Assessment return

Log into your HMRC Government Gateway account and complete your Self Assessment return. For capital gains, complete the SA108 supplementary pages — enter your total disposal proceeds, allowable costs, total gains and total losses. For crypto income, enter amounts on the self-employment or other income pages as appropriate. Reference any payments already made through the Real Time CGT service.

Step 5: Know when you do need an accountant

Most investors with straightforward trading activity can self-file accurately. Consider getting professional help if: you have very high-volume DeFi or on-chain activity with hundreds of complex transactions; you have received an HMRC enquiry letter; you used offshore exchanges with complex structures; you have income through crypto employment or contracting; or your potential liability is six figures or more. For routine investing, DIY is entirely viable.

Frequently asked questions

How long does it take to do your own crypto tax?

With a good UK crypto tax calculator, most investors can complete their calculations in 1–3 hours — mainly the time it takes to download and import all exchange histories. Filing the Self Assessment return itself takes around 30–60 minutes once you have your figures.

What if I make a mistake on my Self Assessment?

You can amend a submitted Self Assessment return within 12 months of the filing deadline. If you discover a significant error after that window, you can make a voluntary disclosure to HMRC. Making a genuine error while trying to comply correctly is treated very differently from deliberate understatement.

Is CryptoTaxUK suitable for self-filing?

Yes — CryptoTaxUK is designed specifically for UK investors who want to calculate their own tax accurately without paying for a specialist accountant. It applies HMRC's exact matching rules, separates income from capital gains, and produces figures you can enter directly into your Self Assessment return.

More UK crypto-tax guides

Crypto Tax Accountant

DIY vs accountant guide

Crypto Self Assessment

Complete filing walkthrough

Crypto Tax Records

What HMRC wants kept

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Educational guidance only. CryptoTax UK is not a regulated tax adviser and the information above does not constitute tax, legal or financial advice. Always confirm your specific position with HMRC or a qualified accountant before filing.