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Register for Self Assessment

Business: Business Tax

Once you’’ve registered for Self Assessment with HM Revenue and Customs (HMRC), you’’ll get a Unique Taxpayer Reference (UTR) number and you can then send your tax return to HMRC.

Before you register

You’’ll need your:

  • National Insurance number
  • personal contact details – eg address
  • business details – eg business address, date you started self-employment or joined a partnership

You must be the ‘nominated partner’ (the partner responsible for sending in the partnership tax return) if you’re registering a new business partnership.


You should register by 5 October following the end of the tax year you need to send a tax return for. This way, you’ll have enough time to complete registration before the tax return and any tax is due. You may have to pay a penalty if you register late.

How to register

How you register depends on your circumstances.

Your circumstance Your reason for registering How to register
New sole trader You’ve not registered before Sole trader – register for Self Assessment
Existing sole trader You’ve registered before and need to re-register (eg you’re starting self-employment again) Existing sole trader – register for Self Assessment
Partnerships You’re the nominated partner and you need to register both yourself and the business partnership Partnership – register for Self Assessment using form SA400
Partner non-individual You’re registering a partner that’s joining a business partnership and they’re not an individual (eg a company or trust) Partner non-individual – register for Self Assessment
Any other reason Eg you or your partner get Child Benefit and your income is over £50,000, you owe tax from investment profits etc Register for Self Assessment using form SA1

How to get an online account

You need an HMRC online account (also known as a ‘Government Gateway’ account) to send a tax return online.

New sole traders and business partnerships can register for Self Assessment and get an online account at the same time.

If you’re not one of these groups, you have to sign up for an online account after you’ve registered for Self Assessment.

It takes 7 working days to set up an online account because HMRC posts you an ‘activation code’ – you need this to ‘activate’ your account. It can take up to 21 days if you’’re abroad.

Register for Self Assessment – forms including SA1, SA400, SA401, deadlines and your Unique Taxpayer Reference (UTR) number