Check whether you need to register
The £1,000 test is gross trading income across your trades before deducting tools, materials or other expenses. It is not a £1,000 profit threshold. Other reasons can require a tax return even with little or no self-employment income; use HMRC's checker for your circumstances.
If your gross trading income is £1,000 or less, you may not need to tell HMRC about it, but there are exceptions. You may also choose to register to claim a loss or for other reasons. The trading allowance has eligibility restrictions and cannot be claimed alongside actual expenses for the same income.
Example: turnover is not the same as profit
Illustration: a plumber earns £3,000 from side jobs and spends £2,400 on allowable materials and other costs. Gross trading income is £3,000, so being left with only £600 does not put them below the £1,000 gross-income test. Keep both income and expense records; do not register using only the amount left in the bank.
What to have ready
- Your personal details and National Insurance number, if you have one.
- Your business contact details and the date you started self-employment.
- Access to the sign-in and identity verification requested by GOV.UK.
- Your existing Unique Taxpayer Reference (UTR), if you already have one.
Register through the official service
- Open GOV.UK's Register for Self Assessment page and choose the option matching your situation.
- If you are new to Self Assessment, follow the self-employed registration instructions and verify your identity as requested.
- If you filed before, follow the instructions to register self-employment or reactivate Self Assessment. Do not create a duplicate record.
- Keep HMRC's confirmation, find your UTR and check you can access the correct filing service before your first deadline.
Registering does not submit a return or pay your tax. Allow time for HMRC to process the registration and any letters or access steps; check current timings in the service rather than waiting until the final week.
When must I tell HMRC?
The usual deadline is 5 October after the end of the tax year in which you need to start Self Assessment. If you began trading during 6 April 2025 to 5 April 2026 and need a return, that usual notification deadline was 5 October 2026. The normal online return and balancing payment deadline is 31 January 2027.
If you have missed the date, register promptly and check what to do with HMRC or an accountant. Do not assume you can wait for HMRC to contact you.
Self Assessment registration is not MTD registration
Self Assessment covers your annual tax return. MTD for Income Tax adds digital records and quarterly updates for those in scope. Its qualifying-income thresholds are separate from the £1,000 gross-trading-income test for Self Assessment. Check whether MTD applies and sign up separately when required.
Fixxa helps organise your everyday business records. Direct HMRC submission is coming soon and is not currently available. Downloading Fixxa does not register you with HMRC.