Getting Your Sole Trader UTR: What You Need to Know

A sole trader UTR, or Unique Taxpayer Reference, is the 10-digit number HMRC gives you when you register for Self Assessment. It identifies you on every tax return, payment and letter for as long as you are self-employed, and often long after. You need a sole trader UTR before you can file a return, and many clients, platforms and construction contractors will ask for it before they pay you. This guide explains how to get your sole trader UTR, how long it takes, where to find it later, and the mistakes that cause delays.

What is a sole trader UTR?

A UTR is a unique 10-digit reference, sometimes shown with a K at the end on online forms. HMRC issues one to each person or organisation that needs to deal with Self Assessment or Corporation Tax. A sole trader UTR belongs to you personally, not to your business name, because a sole trader and their business are legally the same person.

Your UTR is different from your National Insurance number. Your National Insurance number tracks your contributions and State Pension; your UTR tracks your tax returns. You will usually need both.

Sole trader UTR vs company UTR

If you later set up a limited company, the company gets its own UTR for Corporation Tax, separate from your personal one. As a director you may keep your personal UTR too, if you still need to file a Self Assessment return, for example for dividends or other income.

When do you need a sole trader UTR?

You need to register for Self Assessment, and so get a UTR, if you earned more than £1,000 from self-employment in a tax year. You must register by 5 October after the end of the tax year in which you started trading. If you started in August 2025, the deadline is 5 October 2026.

You may also want a sole trader UTR sooner because:

• a construction contractor needs it to verify you under the Construction Industry Scheme (CIS)
• an online marketplace or platform asks for it to set up payouts
• a client's accounts team wants it before adding you as a supplier
• you want to pay voluntary National Insurance to protect your State Pension

How to get your sole trader UTR

Step 1: Check you do not already have one

If you have filed a Self Assessment return in the past, for rental income or as a high earner for example, you already have a UTR. You do not get a new one when you start a business; you tell HMRC about the new self-employment using your existing record.

Step 2: Register for Self Assessment as self-employed

Register online on GOV.UK. You will sign in with Government Gateway or GOV.UK One Login, or create an account as part of the process. HMRC asks for:

• your full name, date of birth and home address
• your National Insurance number
• your phone number and email address
• the date you started self-employment
• the type of business and a short description of what you do
• your business address, if different from home

Registering also sets you up for Class 4 National Insurance on your profits, and lets you pay voluntary Class 2 contributions if your profits are low and you want to protect your State Pension.

Step 3: Verify your identity

You may be asked to prove your identity online, using a passport, driving licence, payslip or other documents, so HMRC can link the registration to you securely.

Step 4: Wait for your UTR

HMRC says you will usually get your UTR by post around 15 days after you register. It takes longer if you live overseas. Your UTR also appears in your Personal Tax Account and the HMRC app once it has been issued.

Step 5: Activate your online account

Some people also receive a separate activation code in the post to switch on Self Assessment online. Use it within the time limit on the letter, or you will need to request a new one.

UTRs for construction subcontractors

If you work in construction as a self-employed subcontractor, your sole trader UTR matters even more. Under the Construction Industry Scheme (CIS), contractors must verify you with HMRC before paying you, and they use your UTR to do it.

• If you are registered for CIS, the contractor deducts 20% from the labour part of your invoice and pays it to HMRC on your behalf.
• If you are not registered, the deduction rises to 30%.
• If you qualify for gross payment status, nothing is deducted, but you must meet turnover and compliance tests.

The deductions count towards your tax bill, so you claim them on your Self Assessment return. Registering for CIS needs your UTR, so apply for both early if you work in construction.

UTRs for partners

A business partnership has its own UTR for the partnership tax return, and each partner also needs a personal UTR to report their share of the profits on their own return. When you register a partnership, the nominated partner registers the partnership and each partner registers individually. If you join an existing partnership, you register yourself as a partner, using your existing UTR if you already have one.

Where to find your UTR later

Once issued, your sole trader UTR stays the same. You can find it:

• in your Personal Tax Account on GOV.UK
• in the HMRC app
• on previous tax returns
• on HMRC letters, such as a notice to file a return or a payment reminder
• on your Self Assessment statements

If you cannot find it anywhere, you can ask HMRC to send it to your address by post. For security, HMRC will not read it out over the phone to just anyone.

What happens after you get your UTR?

Your UTR means you are in the Self Assessment system. From now on you must:

1. Keep records of all your business income and expenses.
2. File a return for each tax year by 31 January after it ends, if you file online.
3. Pay the tax you owe by the same date, plus any payments on account.

Our guide to Self Assessment for sole traders explains each step, from allowable expenses to payments on account. From April 2026, sole traders with qualifying income over £50,000 also need to follow Making Tax Digital for Income Tax.

Common delays and how to avoid them

• Registering late. Leaving it until September risks missing the 5 October deadline if anything goes wrong.
• Wrong address. The UTR comes by post, so make sure HMRC has your current address.
• Registering twice. Creating a second record when you already have a UTR causes confusion and delays. Check old paperwork first.
• Mismatched details. Your name, date of birth and National Insurance number must match HMRC's records exactly.
• Ignoring the activation code. Codes expire; request a new one straight away if yours has.

Sole trader or limited company?

Before you register, it is worth a moment's thought about whether to trade as a sole trader at all. A sole trader UTR is quick and free to get, and the admin is light. A limited company takes a little more setting up and brings yearly filings, but it separates your personal assets from the business and can be more tax-efficient as profits grow. You can start as a sole trader and incorporate later. When the time comes, our company formation service can set up the limited company for you.

Keeping your sole trader UTR safe

Your UTR is not a password, and you will share it with your accountant, CIS contractors and some platforms. But it is personal tax information, and combined with other details it can be used in tax fraud. Only give it to people who genuinely need it, never post it publicly, and be wary of emails or texts asking for it with a link. HMRC does not ask you to confirm your UTR through a link in an unexpected message.

Leaving self-employment

If you stop trading, tell HMRC so your National Insurance and returns are updated. You will usually still need to file a return for the tax year in which you stopped. Your UTR stays the same, so if you go self-employed again later, you use the same number.

Sole trader UTR: quick answers

• Is a UTR free? Yes. Registering for Self Assessment with HMRC costs nothing.
• Can I start trading before I get it? Yes. You can trade from day one; you just need to register by the deadline.
• Does my UTR change if I move house? No. Update your address with HMRC and keep the same UTR.
• Can my accountant use it? Yes, once you authorise them as your agent with HMRC.
• Do I need a new UTR for a second business? No. All your self-employed trades go on the same return under the same UTR.

HMRC's own guidance is on GOV.UK: find your UTR number and register for Self Assessment.

We can register you

We register new sole traders with HMRC, check your details match HMRC's records, and track your sole trader UTR until it arrives, so you can focus on your first customers. See our sole trader registration service.