What is the UTR (Unique Tax Payer Reference) number?

Your individual UTR number, or unique taxpayer reference number (sometimes referred to simply as a taxpayer number) is the series of digits that identifies you to HMRC. As a self-employed person, you’ll need it in a broad range of circumstances.

So what exactly does your UTR mean, how can you obtain one, and how do you know what yours is?

The unique taxpayer reference

Your unique taxpayer reference number, or UTR number, is a unique code that identifies either an individual taxpayer or an individual company. UTR numbers are ten digits long, and may include the letter ‘K’ at the end.

Unique taxpayer reference numbers are used by HMRC to keep track of taxpayers, and is the ‘key’ that the taxman uses to identify all of the different moving parts related to your UK tax affairs. It’s important to keep a note of your UTR.

When do I need to use a UTR number?

You will need your unique taxpayer reference for a number of reasons. The most important of these is to complete your Self Assessment tax return. However, you might also need it if you appoint an accountant or other financial professional to help you deal with your tax affairs. You’re also likely to need your UTR number when you communicate with HMRC for any other reasons. You should consider it as a form of ID.

Registering for a unique taxpayer reference

You’ll be assigned a UTR number when you register as a Self Assessment taxpayer. It’s important to remember that if you fail to notify HMRC that you are self-employed, you may receive a substantial fine.

You will also be assigned a UTR number when you set up a limited company. You should note that this is not the same as your company registration number. When you’re setting up a company, your unique taxpayer reference will be printed in letters from HMRC and may be referred to as a ‘tax reference’ or ‘unique tax reference’.

If you’re applying for a UTR in a hurry, you should remember that it may take some time to arrive. According to HMRC, it can take up to 20 days for your unique taxpayer reference number to be provided. It will be sent by post, but before this happens you will need to pass a number of online security checks.

Information you will need to register

If you are registering for self-assessment, you'll need the following:

  • Full name

  • Current address

  • National Insurance number

  • Date of birth

  • Phone number

  • Email address

  • The date you started being self-employed

  • Type of business

  • Business address

  • Business phone number

Identifying my UTR number

If you’ve lost your unique taxpayer reference number, or if you’re unsure what it is, there are a number of places in which you might be able to find it. When you’re looking, remember that it will be ten digits long, and may be followed by a ‘K’.

You might be able to find your UTR number on the following:

  • On the SA250 form you received when you registered as self-employed

  • On a previous Self Assessment tax return

  • On your first communication from HMRC if you incorporated a limited company

  • On a notice to file

  • On a payment reminder from HMRC