What Is a UTR Number and How Do You Get One?

If you're newly self-employed or setting up as a sole trader, you'll soon encounter the term UTR number. It is one of the most important pieces of identification you'll use in your tax dealings with HMRC — and the sooner you have one, the better.

What is a UTR number?

UTR stands for Unique Taxpayer Reference. It is a 10-digit number that HMRC assigns to every individual registered for Self Assessment. Think of it as your personal tax identifier — separate from your National Insurance number, and specific to Self Assessment and income tax.

A UTR looks something like this: 1234567890. It appears on all official correspondence from HMRC and on your Self Assessment tax return (form SA100).

If you set up a limited company, the company also receives its own separate UTR — distinct from your personal one. As a sole trader, you only ever have one personal UTR.

Why you need your UTR number

Your UTR is required any time you deal with HMRC about your income tax affairs. Specifically, you will need it to:

• File your Self Assessment tax return
• Correspond with HMRC about your tax position
• Enrol for Making Tax Digital for Income Tax, which becomes mandatory for sole traders earning over £50,000 from April 2026
• Authorise an accountant or bookkeeper to act on your behalf with HMRC
• Complete certain client or agency contracts that ask for your tax reference for their own compliance records

Without a UTR, you cannot file a return or formally communicate with HMRC about your Self Assessment affairs.

How to get a UTR number

You do not apply for a UTR directly — HMRC issues one automatically when you register for Self Assessment. Here is how the process works.

Step 1: Create a Government Gateway account

Go to gov.uk and create a Government Gateway account if you do not already have one. You will need your National Insurance number, a valid UK address, and an email address. If you already have a Government Gateway account from another purpose — for example, from checking your tax code or claiming Child Benefit — use that same account.

Step 2: Register as self-employed

Log in to your Government Gateway account and navigate to the Self Assessment registration. Select "sole trader" or "self-employed" as your business type. HMRC will ask for:

• Your date of birth and contact details
• Your National Insurance number
• The date you started self-employment
• A brief description of your business activity

The online registration takes around 10–20 minutes.

Step 3: Receive your UTR

Once registered, HMRC will send your UTR to your registered address by post. This typically takes up to 10 working days. You can also find your UTR in your HMRC online account immediately after completing the registration — log in at gov.uk and look under the Self Assessment section.

When do you need to register?

You must register for Self Assessment by 5 October following the end of the tax year in which you became self-employed. For example, if you started trading during the 2025–26 tax year (6 April 2025 to 5 April 2026), your registration deadline is 5 October 2026. Registering early gives you more time to get your records in order before the January filing deadline.

Where to find your UTR number

Once you have a UTR, it appears in several places:

Source	Where to look
HMRC online account	Self Assessment section — visible after registration
HMRC letters and notices	Printed at the top of all Self Assessment correspondence
Your tax return	Form SA100 and any covering letters from HMRC
P60 (if employed)	Bottom section of your P60 if you also have PAYE income
Accountant records	Any correspondence your accountant has filed on your behalf

What to do if you've lost your UTR number

If you cannot find your UTR, try these steps in order:

1. Check your HMRC online account. Log in at gov.uk — your UTR is displayed in the Self Assessment section. This is the fastest option.
2. Check old HMRC letters. Your UTR appears on all official Self Assessment correspondence from HMRC, including the original "Welcome to Self Assessment" letter.
3. Call HMRC. If you cannot access your online account, call the Self Assessment helpline on 0300 200 3310. Have your National Insurance number ready — HMRC will use it to verify your identity and provide your UTR.

Keeping your UTR secure

Your UTR is sensitive personal information. Treat it with the same care as your National Insurance number. Only share it with:

• HMRC directly
• Your accountant or bookkeeper
• Official parties who have a legitimate tax reason to require it — some agency contracts include this as part of IR35 compliance checks

Do not share your UTR in public forums, with clients who have no genuine need for it, or in communications that could be intercepted. Tax identity fraud — where someone files a fraudulent return in your name — is a real risk and can take considerable effort to resolve with HMRC.

What to do after receiving your UTR

Once you have your UTR, you are set up for Self Assessment. The immediate practical priorities are:

• Start keeping accurate digital records of your income and expenses from day one
• Note the Self Assessment filing deadlines: online returns are due by 31 January following the end of the tax year
• Check whether Making Tax Digital will apply to you — if your combined self-employment and property income exceeds £50,000, MTD for Income Tax is mandatory from April 2026, and you will need HMRC-recognised software

Getting your UTR sorted early removes one piece of admin from an already busy first year of self-employment.