Do I need to register for Self Assessment as a sole trader?

What is Self Assessment?

Self Assessment is the system HMRC uses to collect Income Tax from people whose tax is not taken automatically from their wages or pension. You report your income on a tax return once a year, and the tax is worked out from what you declare.

What is a sole trader?

A sole trader is a self-employed person who runs their own business as an individual. You keep the profits after tax, and you are personally responsible for any business debts. It is the simplest way to work for yourself in the UK.

Do I need to register for Self Assessment as a sole trader?

Yes, if your gross self-employed income was more than £1,000 in the tax year. Gross income means your total takings before you take off any expenses, not your profit. A tax year runs from 6 April to 5 April. So if your sole trader income was over £1,000 between 6 April 2025 and 5 April 2026, you must register for Self Assessment for the 2025 to 2026 tax year.

What if I earned £1,000 or less?

If your gross self-employed income was £1,000 or less, you usually do not need to register or file a return. This is because of the trading allowance, which lets you earn up to £1,000 from self-employment without paying tax on it or reporting it. You still need to register, even under £1,000, if you want to: • claim a loss to set against other income, • pay voluntary Class 2 National Insurance to protect your State Pension, • prove you are self-employed, for example to claim Tax-Free Childcare or Maternity Allowance.

What is the deadline to register?

You must register by 5 October after the end of the tax year in which you started. For income earned in the 2025 to 2026 tax year, the deadline is 5 October 2026. Registering is not the same as paying. Your first tax return and any tax owed are due later, by 31 January after the tax year ends. If you register late, HMRC can charge a penalty, even if your tax bill turns out to be small. Our self-employed tax calendar sets out the other dates that follow once you are registered.

How do I register as a sole trader?

You register online through GOV.UK, and the process sets you up for both Self Assessment and National Insurance at the same time. In outline: 1. Go to GOV.UK and start the "Register for Self Assessment" service. 2. Set up a Government Gateway account, or sign in if you already have one. A Government Gateway account is the login HMRC uses across its online services. 3. Give HMRC your details: name, date of birth, address, National Insurance number, and what your business does and when it started. 4. HMRC sends you a Unique Taxpayer Reference (UTR) by post. A UTR is the 10-digit number that identifies you for Self Assessment. 5. You also receive an activation code to switch on your online account. 6. Once the account is active, you can file your tax return. The UTR and activation code come by post and are not instant, so register in good time rather than close to a deadline.

What information do I need to register?

Have these to hand before you start the online form:

• ☐your National Insurance number
• ☐your personal details: name, date of birth and address
• ☐the date you started trading
• ☐a description of your business or the work you do
• ☐your contact details

Are there other reasons I might need to register for Self Assessment?

Yes. Being a sole trader with income over £1,000 is the most common reason, but you also need to send a Self Assessment return if any of these apply.

What happens after I register?

Once you are registered, you are in the Self Assessment system and file a return for each tax year. For the 2025 to 2026 tax year: • file your online return and pay any tax owed by 31 January 2027, • if your tax bill is more than £1,000, you may also have to make payments on account, which are advance payments towards next year's bill. You stay registered until you tell HMRC you have stopped trading. If you are newly self-employed, our guide to your first 90 days self-employed covers what to set up next.