What is a UTR number?

What is a UTR number?

A UTR number is your 'unique taxpayer reference' number. HMRC assigns each self-assessment taxpayer a different number in order to track their tax records.

All UTR numbers have 10 digits, and sometimes there's a letter 'K' at the end.

Once you get your UTR number it stays with you all your life - just like your National Insurance number.

• Submit your 2023-24 tax return with the Which? tax calculator direct to HMRC

Who needs a UTR number from HMRC?

You only need a UTR number if you submit a self-assessment tax return.

This could be the case if you're self-employed or have set up a limited company, if you owe tax on savings interest, dividends or capital gains, or if you have a total taxable income of more than £100,000.

There are a range of other circumstances where you'll be required to submit a tax return. We explain the full criteria in our guide on how to fill in a self-assessment tax return. 

How to get a UTR number

You won't automatically be given a UTR number. You need to register for self-assessment to be issued with one. Here's how to do it:

• Register for self-assessment online: Before you submit a tax return for the first time - say, after you've started a new business - you need to register for self-assessment, which you can do on the HMRC website. When you do this, you will automatically be assigned a UTR number, which will be sent in a letter through the post.
• Apply over the phone: you can call HMRC on 0300 200 3310 to ask about your UTR number. You may have to provide some details, and they may still direct you to apply online.
• Apply by post: you can write to HMRC to request a UTR number. Be aware that it's likely to take a long time as several letters are likely to go back and forth asking you to provide information.

How long does it take to get a UTR number?

After registering for self-assessment you should receive your UTR number in 10 working days or 21 working days if you're abroad.

Information you'll need to get your UTR number

To register for self-assessment, you'll need the following information:

• Full name
• Current address
• National Insurance number
• Date of birth
• Phone number
• Email address

If you run your own business, you may also need:

• The date you started being self-employed
• Type of business
• Business address
• Business phone number

I've lost my UTR number: what should I do?

If you have already been issued a UTR number but can't find it, you can find it by logging into your personal tax account, or try the HMRC app. 

HMRC has made this YouTube video to show you how to find your UTR number on the app. 

Alternatively, you can call HMRC's self-assessment helpline (0300 200 3310). To help them find your UTR number, you should have your National Insurance number to hand.

Note that HMRC cannot give your UTR number over the phone, and will have to post it to you - which could take 10-15 days.

Submitting a tax return without your UTR number could result in a fine, as HMRC may not be able to match your return to their records before the submission deadline.

• Find out more: late tax returns and penalties for mistakes

Your UTR questions answered

Below, we tackle common questions about UTR numbers.