What Is a UTR Number?

A Unique Taxpayer Reference (UTR) is a 10-digit number that HMRC uses to identify you as a taxpayer. It's your personal tax identification number for all Self Assessment matters.

The UTR is:

  • Permanent – Once issued, it stays with you for life (unless in rare circumstances you need a replacement)
  • Unique to you – No two taxpayers share the same UTR
  • Different from your NI number – Your National Insurance number is for NI contributions; your UTR is specifically for Self Assessment

The format is simply 10 digits, such as: 1234567890. There are no letters or special characters.

Why You Need It

Your UTR is essential for various tax-related activities:

  • Filing Self Assessment returns – You cannot submit your annual tax return without your UTR
  • Setting up your online HMRC account – Required to access Self Assessment online services
  • Paying tax – Your UTR is referenced when making tax payments to ensure they're allocated correctly
  • Communicating with HMRC – They'll ask for it to locate your records
  • Working with accountants – Your accountant needs it to act on your behalf

Some clients and platforms may also request your UTR to verify you're registered for Self Assessment. This is particularly common in sectors where IR35 compliance is scrutinised, or when working with larger organisations.

How to Get One

You receive a UTR automatically when you register as self-employed with HMRC. You don't need to apply separately—it's part of the registration process.

Steps to Register and Receive Your UTR

  1. Register for Self Assessment at gov.uk/register-for-self-assessment
  2. Complete the online form with your personal and business details
  3. Submit your registration
  4. Wait for your UTR to arrive by post

You'll need a Government Gateway account to register online. If you don't have one, you'll create it during the registration process.

For detailed instructions, see our guide on How to Register as Self-Employed in the UK.

How Long It Takes

After registering online, HMRC will send your UTR by post:

  • UK address: Allow 10 working days
  • Overseas address: Allow up to 21 working days

The letter containing your UTR is sent to the address you provided during registration. Make sure your registered address is correct—HMRC won't email or text you this information for security reasons.

💡 Practical Example

Sophie registered as self-employed on Monday, 10 February. She received her UTR letter on Friday, 21 February—exactly 9 working days later. The letter included her UTR, instructions for setting up her online account, and information about her Self Assessment obligations.

Need It Urgently?

If you registered more than 10 working days ago and haven't received your UTR, or you need it urgently, you can:

  • Call HMRC's Self Assessment helpline: 0300 200 3310
  • They can tell you your UTR over the phone after verifying your identity
  • Lines are open Monday to Friday, 8am to 6pm

Be prepared for wait times, especially during busy periods (January is particularly congested).

Where to Find It If Lost

Lost or forgotten your UTR? Here's where to find it:

Check Previous Documents

  • Previous Self Assessment tax returns – Your UTR appears on all returns
  • HMRC letters and notices – Including payment reminders, statements, and correspondence
  • Payment reminders – Letters about upcoming tax payments include your UTR
  • Your accountant's records – If you use one, they'll have it on file

Online Methods

  • Personal Tax Account – Log in at gov.uk/personal-tax-account to view your UTR
  • HMRC app – Your UTR is visible in the official HMRC app once logged in
  • Government Gateway – If you've previously accessed Self Assessment services, your UTR may be visible

Contact HMRC

If you can't find it anywhere:

  • Phone: 0300 200 3310 (Self Assessment helpline)
  • Online: Use HMRC's online services to request a reminder

You'll need to verify your identity—have your National Insurance number, date of birth, and address ready.

When You Need to Provide It

You'll use your UTR in several situations:

Always Required

  • Filing your annual Self Assessment tax return
  • Making tax payments to HMRC
  • Corresponding with HMRC about your tax affairs
  • Authorising an accountant to act on your behalf

Sometimes Requested

  • Recruitment agencies – Often ask for your UTR to confirm you're set up for self-employment
  • Large clients – May request it as part of their onboarding or compliance processes
  • Mortgage and loan applications – Lenders sometimes want to verify your self-employment status
  • Freelance platforms – Some platforms request it for tax reporting purposes

Security Notes

While your UTR isn't as sensitive as your National Insurance number, you should still:

  • Only share it with legitimate entities who have a genuine need
  • Be wary of unsolicited requests for your UTR (potential phishing)
  • Never share it publicly or on social media
  • Store it securely with your other important documents

💡 Practical Example

When Michael started working with a new client—a large marketing agency—they asked for his UTR during onboarding. This was part of their standard contractor verification process. He provided it alongside his business address and bank details for payment. The agency used it to confirm he was registered for Self Assessment, as required by their compliance procedures.

Quick Reference

  • Format: 10 digits (e.g., 1234567890)
  • Issued by: HMRC, automatically upon Self Assessment registration
  • Delivery: By post, 10 working days (UK) or 21 days (overseas)
  • Helpline: 0300 200 3310
  • Online access: gov.uk/personal-tax-account

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