📝 Description
Learn how cryptocurrency transactions are reported to HMRC through the Self Assessment tax return system in the United Kingdom.
⚠️ Warnings
Crypto transactions are not declared on a dedicated "crypto form"; they are reported across different sections of your Self Assessment based on the nature of the income or gain.
Carrying out crypto activities as a business (such as professional mining) changes your reporting requirements from Capital Gains Tax to Self-Employment income.
⚖ How to Declare Crypto Taxes
In the United Kingdom, crypto taxes are reported through the Self Assessment tax return system managed by HMRC. Crypto transactions are reported across different sections of the Self Assessment depending on the type of income or gain involved.
The main forms used are:
SA100 – Main Self Assessment tax return
SA108 – Capital Gains Tax summary
SA103 – Self-employment income (if applicable)
The main Self Assessment form (SA100)
The SA100 is the core tax return submitted by individuals. It contains the main summary of your income for the tax year and acts as the central document linking all additional pages together.
Crypto activity appears on the SA100 if you received crypto as income, such as:
Staking rewards
Mining income
DeFi lending rewards
Certain airdrops
Referral bonuses
These amounts are typically reported in the Miscellaneous income section if the activity is not considered a business. If crypto activities are carried out as a business (for example, professional mining), the income must instead be reported under self-employment income on form SA103.
Capital gains reporting (SA108)
Most crypto tax reporting in the UK occurs through Capital Gains Tax, which is declared on the SA108 form whenever you dispose of cryptoassets.
A disposal includes:
Selling crypto for fiat currency
Exchanging one cryptoasset for another
Paying for goods or services using crypto
Gifting crypto (except to a spouse or civil partner)
The SA108 does not require a list of every individual transaction. Instead, it requires summary totals:
Field | Description |
Total proceeds | Total value of all disposals |
Allowable costs | Total cost basis of the assets sold |
Total gains | Gains before deductions |
Total losses | Losses during the year |
Net gain | Final taxable gain after adjustments |
These values are calculated using HMRC’s cost basis rules (same-day rule, 30-day rule, and Section 104 pooling).
Optional: Self-Employment form (SA103)
If you carry out crypto activities as a business, you must report your income through the SA103 Self-Employment pages.
This applies to situations such as:
Professional mining operations
Running a crypto trading business
Operating a validator or staking service as a business
In these cases, crypto income is treated similarly to business revenue, and expenses related to the activity may be deductible. Most individual investors will not need this form.
💡 Recommendations
Unlike some other countries, the UK does not require taxpayers to declare foreign crypto accounts or wallets. HMRC only requires taxpayers to report taxable income and gains, regardless of where the crypto assets are held.
Use specialized crypto tax software like Waltio to automatically calculate your summary totals and generate a Capital Gains summary for form SA108.