A Unique Taxpayer Reference, usually called a UTR, is HMRC’s 10-digit reference for your tax record. As a sole trader, you normally receive one when you register for Self Assessment. If you already have one, look it up before starting a fresh application.

See the end of year Self Assessment report or explore quarterly reports.

What does a UTR look like?

It is 10 digits, for example the fictional number 1234567890. It may be labelled tax reference on HMRC paperwork. It is different from your National Insurance number, your online sign-in details and a company registration number.

For certain Self Assessment payments you add K after the UTR to create the payment reference. That does not make K part of the UTR itself.

How to get a UTR as a new sole trader

• Check whether you need Self Assessment registration. Gross trading income over £1,000 normally means you do.
• Start at HMRC’s official registration service.
• Select the route that matches your circumstances, including whether you have registered before.
• Provide the requested identity, contact and business details accurately.
• Keep the registration confirmation and look out for HMRC’s correspondence.

You do not need to pay a third party just to obtain a UTR from HMRC. Our registration guide covers the wider process.

How long does it take?

HMRC says a UTR usually arrives by post around 15 days after registration, with longer times overseas. Processing can vary. Check the current expected-reply guidance linked from HMRC’s UTR page rather than treating that as a guaranteed delivery date.

Where to find an existing UTR

• Your Personal Tax Account.
• The HMRC app.
• Previous Self Assessment returns.
• HMRC notices to file, payment reminders and other tax correspondence.

If an accountant acts for you, ask whether they hold it. Use your individual Self Assessment reference for your sole trade; a limited company has a separate tax reference.

What if it is lost or never arrives?

Check your online account and letters first. If you still cannot find it, use HMRC’s find-your-UTR guidance and the contact route provided there. Check the address used at registration and the expected response time. Avoid repeated registrations simply because the post has not arrived.

Do I need a new UTR if I start trading again?

You will generally keep your individual UTR, but you may need to reactivate Self Assessment or tell HMRC about restarting self-employment. Follow the registration route for people who have registered before. Starting a new sole trade does not mean automatically applying for a second personal UTR.

Keep it safe and prepare your records

Share the reference only where there is a legitimate reason, such as dealing with HMRC, an authorised accountant or CIS verification. Do not put it on public social profiles or use it as a password.

While waiting, record your income and expenses and keep receipts. You do not need the letter to start organised bookkeeping. Next, read when your first return is due and how to pay your first bill.

Sources and further help

Checked 25 October 2026. Find your UTR · Register or reactivate Self Assessment. Guidance for straightforward sole traders; individual circumstances can change the answer.