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Self-assessment tax return

What is a UTR number?

By Ian Robinson

Article 10 of 10

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What is a UTR number?

Find out what a UTR number is, how you get one and what you use it for.

A UTR number is a ‘unique taxpayer reference’ number. HMRC will issue you with a UTR if you register for self-assessment tax (meaning you’ll need to fill in a tax return).  All UTR numbers have 10 digits.

Once you get your UTR number, it stays with you all your life, in the same way as your National Insurance number.

If you stop submitting a self-assessment tax return, your UTR number becomes dormant, but if you start again it’s reactivated.    

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How do I get a UTR number?

You’ll get a UTR number if you register to fill in a tax return. You would do this if, for example, you were setting up as self-employed (a sole trader). HMRC will also issue a UTR number if you set up a limited company.

When you register as a new business with HMRC, you automatically register for self-assessment tax returns and Class 2 National Insurance at the same time.

You need to register as soon as you can after starting your business. At the latest, you should register by 5 October in your business’s second tax year.

Registering for self-assessment can take up to 10 working days because HMRC needs to post you an activation code. You’ll be prompted for this when you first log in to your online tax account (also known as a Government Gateway account).

Where do I find my UTR number?

If you’ve already been issued with a UTR number, you can find it on a previous tax return and other documents you’ve received from HMRC, such as a notice to complete a tax return or a statement of account.

Your 10-digit UTR may also be called a ‘tax reference’.

When you complete an online tax return, your UTR appears on the second page (in ‘Tell us about you’), in a box below your last name and above your National Insurance number.

If you submit a paper tax return, your UTR appears on the first page, just above your National Insurance number.

If you have already been issued with a UTR number but can’t find it, call HMRC’s self-assessment helpline (0300 200 3310).

What are UTR numbers used for?

Some companies accept a UTR as proof that you are self-employed. UTRs are only proof that you have registered to submit a self-assessment tax return, though.

  • Last updated: April 2017
  • Updated by: Gareth Shaw
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