Your crypto tax records can become incomplete when you treat three dates as one. Those dates are an HMRC announcement, an effective date, and a reporting deadline. This matters before completing Self Assessment. Exchanges may collect data that helps HMRC compare activity with your return.
Important: your tax position depends on your own transactions and circumstances.
For UK Tax News & HMRC Updates, tax rules already apply to taxable disposals and income. CARF does not create a new tax. From 1 January 2026, relevant UK cryptoasset service providers must collect reportable customer and transaction data. First reports are generally due in 2027. Verified HMRC updates, practical actions, and record evidence help you respond accurately.
CARF starts data collection, not a new tax
CARF requires relevant UK cryptoasset service providers to identify reportable customers. They must collect transaction information from 1 January 2026.
CARF timeline for a UK customer: providers begin due diligence and collect reportable data from 1 January 2026. First annual reports are generally due during 2027. International information exchanges can then follow under OECD arrangements. Tax on a 2024 or 2025 disposal does not wait for these dates.
A UK exchange may ask for your legal name, address, and date of birth. It may also ask for your tax residence and tax identification number. This could be your UTR or National Insurance number. It may ask if you pay tax outside the United Kingdom.
These checks also sit alongside anti-money-laundering duties. Those duties come from the Money Laundering Regulations 2017.
CARF changes data collection, not the date when your tax becomes due.
HMRC can look before 2026
CARF does not create a safe period for old activity. HMRC can seek information under existing legal powers. It can review bank payments and obtain platform records. It can also use data from overseas tax authorities.
A nudge letter does not prove HMRC calculated your tax correctly. It is still a reason to check your records quickly.
CARF data collection and reporting scope: CARF data goes beyond an exchange app balance. UK cryptoasset service providers may need self-certification details. These include identity, address, tax residence, and tax identification number. Providers must check this information where the rules require it.
Their HMRC reports can cover exchanges involving cryptoassets. They can also cover transfers, values, and token quantities. The reporting period is usually the calendar year. Data from 2026 is expected in the first HMRC report by 31 May 2027.
This is a provider duty, not a separate Self Assessment return. HMRC may later use this data for compliance work. OECD information exchange may also share it between countries.
When crypto activity creates CGT or income tax
Giving up ownership can create a cryptoasset disposal for CGT. This includes a sale, swap, making a purchase, or gift. The value is usually measured in pounds at the transaction time.
| Activity | Usual tax starting point | GBP value needed | Keep this evidence |
|---|
| Sell Bitcoin for GBP | CGT disposal | Sale time | Trade record, fee, bank receipt |
| Crypto-to-crypto swap | CGT disposal | Swap time | Both token amounts, rate, fee |
| Spend crypto | CGT disposal | Payment time | Invoice, wallet transaction hash |
| Staking or mining reward | Possible Income Tax first | Receipt time | Reward log, platform terms, wallet record |
| Gift to another person | Usually CGT disposal | Gift date | Recipient, date, market value basis |
| Transfer between own wallets | Usually not a disposal | Transfer record | Both wallet addresses and hashes |
Swaps need share-pool calculations
A swap from Bitcoin into Solana can trigger CGT. This applies even when no cash reaches your bank. The gain is broadly the disposal value less allowable cost and relevant fees.
The annual exempt amount is £3,000 for 2024/25 and 2025/26. It covers total gains for the year. It does not apply to each trade.
A crypto swap can be taxable even when your bank balance never changes.
Airdrops and employment differ
Not every airdrop is taxable income when you receive it. The result depends on why you received it. It also depends on whether it came from a trade or service.
Crypto paid by an employer is usually employment income. PAYE and National Insurance can then apply. These issues go beyond a simple CGT calculation.
Airdrops, employment and losses need separate records: An airdrop may fall outside Income Tax at receipt. This can apply if it was not payment for services. It can also apply if you did not receive it through a trade.
The facts still matter for a later disposal. The token's sterling value also matters then. Keep payslips, payroll records, award terms, and GBP values for employment crypto.
For staking rewards, keep reward times and token quantities. Keep platform statements and valuation evidence too. A fall in token price alone does not always create an allowable CGT loss.
Keep disposal records, fees, and wallet hashes. Keep evidence for a claimed loss or negligible-value position.
Build records before your self assessment deadline
An exchange dashboard is not a UK crypto tax calculator.
A practical crypto tax record route
1. Download
Exchange, wallet and bank histories
2. Reconcile
Match transfers and fees
3. Classify
Disposal, income or own transfer
4. Report
CGT, income and losses
Keep calculations, GBP rates, transaction hashes, and source files. HMRC may ask how you reached a number, not just what you entered.
HMRC generally requires Self Assessment records for at least 5 years after the 31 January filing deadline. For the year ending 5 April 2025, keep records until at least 31 January 2031. Keep the original export with any spreadsheet or software output.
Your records should show where every reported pound figure came from.
Fix errors before enforcement begins
You can normally amend a tax return within 12 months of the 31 January filing deadline. Older errors may need a disclosure route. Late tax can also lead to interest.
Penalties depend on the facts. HMRC will consider whether an error was careless or deliberate. It will also consider whether HMRC prompted the disclosure.
Correcting returns and voluntary disclosure: If your return is within its amendment window, correct the relevant CGT or Income Tax entries quickly. This is usually the simplest route. A voluntary disclosure may be needed after that window closes.
Make a disclosure before HMRC opens an enquiry or contacts you about the issue. An unprompted disclosure does not remove tax or statutory interest.
It can affect HMRC's penalty decision. It can also show the quality of your cooperation.
A nudge letter is not a tax assessment. It should still prompt a review of crypto records and past reporting. Seek professional advice for incomplete records, claimed losses, offshore platforms, or errors across several tax years.
Common questions
Do I pay tax only when I cash out crypto?
No. Selling crypto for GBP, swapping tokens, spending crypto, and many gifts can create CGT disposals. The £3,000 annual exempt amount covers total gains in that tax year. It does not cover only bank withdrawals.
Will CARF create a new crypto tax in 2026?
No. CARF starts provider data collection from 1 January 2026. It is mainly a reporting framework. Existing CGT and Income Tax rules apply before and after that date.
Can HMRC see crypto transactions from before 2026?
Yes. HMRC can review earlier periods through information powers, exchange records, bank data, and international cooperation. CARF does not limit an enquiry into 2021, 2022, or later tax years.
How long should I keep crypto tax records?
Keep Self Assessment records for at least 5 years after the 31 January filing deadline. Keep exchange exports, wallet addresses, hashes, GBP values, and fees. Also keep records of transfers between your own wallets.
Are staking rewards always taxed as income?
No. Staking rewards often need an Income Tax review when received. The answer depends on the facts and activity. A later sale can also create CGT using the receipt value in the cost calculation.
This general checklist is not personal tax advice. In some cases, seek advice if you run a crypto business or trade frequently as a business. Do the same for complex DeFi, loans, derivatives, or liquidity pools. Seek advice for employment tokens, major losses, or non-standard UK residence or domicile issues. This also applies during an HMRC enquiry or where earlier returns may be wrong. If you are not UK tax resident, check rules in your tax-resident jurisdiction.
Your next decision is simple: gather records before the next Self Assessment deadline. Separate income from disposals. Keep proof for every GBP valuation.
Do not wait for a CARF request or an HMRC letter. A clear transaction history supports an accurate return, a loss claim, or a voluntary correction.
