A tax app can import thousands of crypto transactions. It may still leave you unable to explain a wallet transfer to HMRC.
A non-custodial wallet does not give HMRC automatic access to your funds. You still must keep evidence linking addresses, movements and tax treatment.
An HMRC-ready record proves each movement
An HMRC-ready crypto record shows what happened, when it happened, its GBP value and whether ownership changed.
Record every taxable and non-taxable event
Record sales, crypto-to-crypto swaps, purchases, gifts and spending. Also record staking rewards, mining income, airdrops, DeFi transactions, NFT transactions and transaction fees.
A transfer between wallets you own is usually not a disposal. It still needs a record showing why it was a transfer.
Capture these fields for each transaction
Each transaction entry needs enough detail for another person to follow. They should not need to guess.
- Date and time: keep the timezone when the source shows one.
- Transaction type: purchase, sale, swap, reward, fee, gift or personal transfer.
- Asset and quantity: for example, 0.015 BTC or 250 USDC.
- GBP value: the value at the transaction time, with the pricing source kept.
- Fees: the asset, quantity and GBP value of network or platform fees.
- Counterparty or platform: such as Kraken, Coinbase, Binance or a known recipient.
- Transaction ID: the blockchain reference, often called a TXID.
- Origin and destination: the sending and receiving wallet or exchange account.
Keep source evidence beside the calculation. Save exchange CSV exports, trade confirmations, wallet transaction links and GBP price evidence. A tax report without source records is like a bank statement with every payment description removed.
Separate records from tax conclusions
Cryptoasset recordkeeping, tax preparation and tax filing are related jobs. They are still separate jobs.
Recordkeeping keeps the raw facts. These include exchange exports, wallet addresses, transaction IDs, GBP values and notes for personal wallet transfers.
Tax preparation applies the relevant rules to those facts. This includes finding income events and working out gains or losses from disposals.
Filing is the final step. You enter the figures in Self Assessment and keep the working papers behind them.
A crypto tax report can speed up preparation. It does not guarantee correct categories, prices, transfer matching or tax treatment.
You remain responsible for checking the figures before filing a return.
Choose a system that matches your activity
A hybrid system is usually the safest choice. It suits UK holders using several exchanges and self-custody wallets.
| Method | Best fit | Typical annual cost | Manual checking | Transfer matching |
|---|
| Spreadsheet | One exchange, low volume | £0 to £30 | High | Manual |
| Tax app | Several platforms, clear history | Often £40 to £200+ | Medium | Automated, then checked |
| Hybrid system | Wallets, exchanges or DeFi | App cost plus records time | Medium | App matched against register |
⭐
Picked for you
A paper ledger can keep wallet addresses, export locations and monthly checks separate. Keep it separate from passwords and recovery words. It works best as a backup index, not instead of encrypted digital evidence.
- Keeps a dated list of exchanges, public addresses and CSV export locations
- Creates an offline monthly reconciliation checklist for tax records
- Avoids putting seed phrases in a cloud-based tax spreadsheet
View on Amazon →
Test the app before trusting it
Before choosing a crypto tax app, check every chain, exchange and wallet you use. Do not rely only on the assets it advertises.
Check if it imports full API histories and exchange CSV exports. It should identify transfers between your addresses and retain transaction-level links.
It should not replace those links with a summary. For DeFi and NFT transactions, check that you can edit labels.
Check if you can split one blockchain event into its economic parts. Make sure you can keep notes.
A useful system should export a readable crypto tax report. It should keep GBP value sources and show crypto transaction fees separately.
It should offer strong account security. It should also explain how it stores and deletes your data.
Build a wallet register HMRC can follow
A master wallet register links each exchange account and public address to its owner. It does this without exposing security credentials.
Use this master register template
Keep the register in an encrypted file or secure document store. Do not add passwords, private keys or seed phrases.
| Account or wallet |
Public address or account ID |
Owner |
Evidence location |
Last checked |
| Kraken account |
Account reference |
Individual |
CSV archive, 2026 folder |
31 March 2026 |
| Ledger Bitcoin wallet |
bc1... Public address |
Individual |
Withdrawal confirmation and TXID |
31 March 2026 |
| MetaMask address |
0x... Public address |
Individual |
Explorer link and wallet export |
31 March 2026 |
For each entry, add the provider, wallet type and opening date. Add the location of its CSV, PDF or blockchain evidence.
A public address is safe to record for tax evidence. A seed phrase is not.
Prove a personal transfer clearly
Keep the sending platform's withdrawal confirmation, receiving address and TXID. Add a short note, such as “personal transfer from Kraken account to Ledger address”.
Record the fee separately if it reduces the received amount.
Keep keys out of tax records
Never share private keys, login passwords, recovery codes or seed phrase backups. Do not give them to an accountant or tax app.
A seed phrase is like a master key to a safe. Anyone holding it may control the assets.
Self-custody needs evidence, not key sharing
A non-custodial wallet does not give HMRC automatic access to your funds. It does not reduce your recordkeeping duty.
Store evidence with sensible access controls
Save exports in at least two places. Examples include an encrypted local drive and an encrypted backup.
Limit access to people who need it. Review access after changing accountants or devices.
A cryptoasset service provider may hold identifying information about you. This may include your name, contact details, account history and tax-residence details.
The provider may need to give relevant information to tax authorities. This can happen under applicable reporting rules.
This differs from automatic access to a non-custodial wallet. HMRC does not control self-custody assets because an address exists on a public chain.
Blockchain transaction links may still connect to you. Exchange withdrawals, bank payments, account checks or your records can create that link.
Keep transfer evidence showing the route from a verified exchange account. Link it to each personal address.
Keep private keys and recovery phrases completely outside tax records.
Reconcile monthly before filing self assessment
A monthly reconciliation checks imported history against real balances. It finds errors before they reach a tax return.
Follow this monthly reconciliation routine
- Export or refresh each exchange and wallet transaction history.
- Compare actual asset balances with the balances shown in the app.
- Check for duplicate API and CSV imports on the same date and amount.
- Match outgoing and incoming transfers between addresses in your register.
- Check negative balances, missing historic GBP prices and uncategorised entries.
- Save a dated report copy and note every correction made.
A negative balance often means purchase history is missing. It can also mean an internal transfer was not matched.
Do not ignore it because the final report produces a number.
Know what needs manual review
Review crypto-to-crypto swaps, staking rewards, mining income and airdrops. Also review liquidity-pool events, bridges, token wraps and NFT transactions.
Fees may affect allowable expenses or acquisition and disposal calculations. The result depends on the facts.
This guidance matters less if you have never acquired, disposed of, received or transferred cryptoassets. It cannot replace tailored advice for commercial trading, companies, complex DeFi protocols or an HMRC enquiry.
FAQs
Do I need records for crypto transfers between my wallets?
Yes, record transfers between wallets you own. The evidence shows they were not sales or gifts.
Keep both addresses, the TXID, the date, the fee and a note confirming common ownership.
How long should I keep UK crypto tax records?
Keep crypto tax records for at least five years after the 31 January filing deadline. This applies to the relevant tax year.
Keep them longer if HMRC checks a return. Also keep them where a disposal relies on older acquisition evidence.
Can HMRC see my non-custodial wallet?
HMRC does not automatically access a non-custodial wallet because you own one. Public blockchain activity may still link to you through other records.
These records may include exchange, bank, identity or supporting records.
Is Koinly enough for a UK tax return?
Koinly can organise imports and produce calculations. It is not enough when source history is incomplete or transactions have wrong labels.
Check transfer matching, historic GBP values and Section 104 pool treatment before filing.
Do crypto-to-crypto swaps need to be recorded?
Yes, a crypto-to-crypto swap normally needs recording. It may be a disposal for Capital Gains Tax.
Record both assets, quantities, GBP values, fees, time and transaction evidence.
Should I give my accountant my seed phrase?
No, never give an accountant your seed phrase, private key or exchange password. Give public addresses, CSV exports, transaction IDs and read-only evidence instead.
What is the best crypto tax calculator UK users can use?
The best UK crypto tax calculator imports your actual exchanges and wallets. It supports your chains and allows manual corrections.
Test between 10 and 20 known transactions before relying on a final report.
Set up your recordkeeping this week
Start by listing every exchange, wallet and public address you have used. Download source exports before a platform closes or changes its history view.
Next, choose the method that fits your activity. Complete one monthly reconciliation before preparing Self Assessment.
The essentials:- A tax app helps, but it cannot repair missing history or prove wallet ownership alone.
- Record the date, GBP value, fees, TXID and both ends of each meaningful movement.
- Keep a separate register for exchanges and public addresses, never seed phrases or private keys.
- Reconcile monthly to fix duplicate imports and false disposals before Self Assessment.
Learn more
Here are some additional resources on this subject:
