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 2021-22 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.
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 to self-assessment tax returns.
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, 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.
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 commonly-asked questions about UTR numbers.
Do I have to pay to apply for a UTR number?
No, it's free to get a UTR number.
Where can 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 number will be labelled as 'UTR', ‘tax reference’ or 'Official Use'.
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.
You'll also find your UTR number on notices to file a return, payment reminders and in your HMRC online account.
How do UTR numbers for business partnerships work?
If you're in a business partnership, you need a UTR number for the firm, as well as a UTR number for each partner, in order to file online.
You'll need to submit a company tax return for the firm, as well as one for your own income and expenses.
What are UTR numbers used for?
Your UTR number is what HMRC uses internally to track your tax obligations and match your records to your payments.
While some companies may accept a UTR as evidence that you are self-employed, you should note that UTRs are only proof that you have registered to submit a self-assessment tax return.
When will I need my UTR number?
You'll need your UTR number when completing a self-assessment tax return, and when working with an accountant or someone else helping you with your financial affairs.
HMRC will also ask for your UTR if you pre-pay your tax in instalments (known as payment on account).
You can find out more in our guide to paying tax as a self-employed person.
How can I reactivate my UTR number?
If you stop submitting a self-assessment tax return, your UTR number will become dormant.
When you start submitting tax returns again, it will automatically be reactivated.
What happens if I use the wrong UTR number?
Entering the wrong UTR number is one of the most common mistakes made on tax returns every year.
Double-check the number is correct before submitting your return. You may have to pay a fine if HMRC decide you have not shown enough care while filling out the forms.
If you realise you've submitted your return with the incorrect UTR, contact HMRC by phone or in writing to correct the error.