What Is a UTR Number in the UK? How to Get It and Why It Matters

If you are starting a business in the UK, going freelance, or earning income outside of a regular salary, there is one number you will need before you can deal with HMRC properly your: UTR number. Most new business owners hear about it for the first time when they are already in the middle of setting something up, which is why it is worth understanding what it is, who needs it, and how to get it before it becomes urgent.

This guide covers everything you need to know about UTR numbers in plain English, no jargon, no confusion.

What Is a UTR Number?

A UTR number, short for Unique Taxpayer Reference, is a 10-digit number issued by HM Revenue and Customs (HMRC) to identify you or your business within the UK tax system. It is your personal tax ID, used every time you file a Self Assessment tax return, contact HMRC about your tax affairs, or deal with certain financial and compliance processes.

The number looks something like this: 1234567890

It is sometimes written with a space in the middle (1234 567890) and, in some cases, may have the letter K at the end. Either format is valid. What matters is the 10 digits that are your unique identifier.

One of the most important things to understand about your UTR is that it is yours for life. Once HMRC assigns it to you, it never changes, even if you stop trading, change your business structure, or move address.

Who Needs a UTR Number?

Not everyone in the UK needs a UTR. If you are a standard employee paid through PAYE and have no other income to declare, you will not need one unless HMRC specifically asks you to register for Self Assessment.

You will need a UTR number if you are:

• Self-employed as a sole trader and earning more than £1,000 per year
• A freelancer or contractor who invoices clients directly
• As a limited company director, your company will have its own UTR, and you may also need a personal one for Self Assessment
• A business partner in a registered UK partnership
• A landlord receiving rental income
• An investor with untaxed investment income
• Earning over £150,000 per year through PAYE HMRC may still require you to file a Self Assessment
• A non-UK resident with UK-sourced income, such as rental property

If you are unsure whether you need one, the safest approach is to check on the HMRC website or speak to an accountant. Failing to register when you should have done so can result in penalties from HMRC.

Why Does Your UTR Number Matter?

Your UTR is not just an administrative formality. It is the thread that ties all your tax activity together inside HMRC's systems. Without it, several things become impossible or significantly more complicated.

Filing your Self Assessment tax return requires your UTR; you cannot submit the form without it. If you use the wrong UTR or try to file without one, HMRC will not be able to match the return to your record, and you could face penalties even if you filed on time.

Paying your tax bill correctly depends on your UTR being quoted accurately. If you make a payment to HMRC without your UTR, the payment can go unallocated — meaning HMRC does not know you have paid, and you could receive automatic late payment fines and interest charges even though the money left your account.

Opening a business bank account, many UK business banks and digital banks will ask for proof of your tax registration, which means providing your UTR. Tide, Starling, and Monzo Business may all request this during their onboarding process.

Working with an accountant requires them to have your UTR so they can act on your behalf and submit returns or correspondence to HMRC.

Registering for the Construction Industry Scheme (CIS), if you work in construction as a subcontractor, your UTR is required to register and to claim CIS tax refunds.

The short version: your UTR is your gateway to managing taxes properly in the UK. The sooner you have it, the better.

How to Get a UTR Number

You do not apply for a UTR number directly. HMRC issues it automatically when you complete the relevant registration. The process depends on whether you are self-employed or setting up a limited company.

If you are self-employed or a sole trader

1. Go to gov.uk/register-for-self-assessment
2. Select the self-employed option and create or log in to your Government Gateway account
3. Verify your identity using your National Insurance number and either a UK passport, P60, or recent payslip
4. Complete the registration form with your personal details, the date you started trading, and your business information
5. Submit the form, HMRC will process your registration and send your UTR number by post

Important deadline: You must register by 5 October following the end of the tax year in which you started trading. So if you started trading in the 2025/26 tax year, you must register by 5 October 2026. Missing this deadline can trigger a penalty.

If you are setting up a limited company

When you register a limited company with Companies House, HMRC is automatically notified. Your company UTR will be sent by post to your registered office address within approximately 14 days of incorporation. You do not need to register separately for this; it happens automatically. As a director, you may also need a personal UTR if you take a salary or dividends that put you above the Self Assessment threshold.

How long does it take?

After registering, you should receive your UTR number by post within 10 to 15 working days if you are based in the UK. If you are overseas, the process can take up to 21 working days. HMRC sends it by post for security reasons; they will not give it out over the phone or by email.

How to Find Your UTR Number If You Already Have One

If you have registered before but cannot remember where you put your UTR, there are several ways to track it down.

Check your HMRC correspondence. Your UTR appears on most letters from HMRC, tax return reminders, payment notices, and your original SA250 welcome letter. It is usually printed near the top of the document and may be labelled as tax reference or UTR.

Log in to your Personal Tax Account. Visit the HMRC website and sign in with your Government Gateway credentials. Navigate to the Self Assessment section, and your UTR will be displayed there.

Use the HMRC app. Download the HMRC app on your phone, log in, and check the Self Assessment section. Your UTR is visible directly in the app.

Check old tax returns. If you have filed Self Assessment returns in previous years, your UTR will appear on every one of them.

Call HMRC. If none of the above work, call the Self Assessment helpline on 0300 200 3310 (Monday to Friday, 8 am to 6 pm). They will verify your identity and send your UTR to your registered address by post; they cannot give it to you over the phone.

How to Keep Your UTR Secure

Your UTR should be treated like sensitive financial information similar to your bank account details. While it cannot be used on its own to access your HMRC account, someone who has it could potentially impersonate you in written correspondence with HMRC.

A few simple rules to follow:

• Do not share your UTR publicly or post it anywhere online
• Only give your UTR to your accountant, bookkeeper, or a financial institution that has a legitimate reason to ask for it
• Be cautious of unsolicited emails or phone calls asking for your UTR. HMRC will never contact you this way to ask for it
• Store it somewhere secure — a password manager, a locked note, or a safe physical document

UTR Number vs National Insurance Number: What Is the Difference?

These two numbers are often confused by people new to UK tax. They serve different purposes and should not be mixed up.

Your National Insurance (NI) number has letters and numbers (for example, AB 123456 C) and is used to track your National Insurance contributions, benefits entitlements, and your State Pension. You receive this when you turn 16.

Your UTR number is a 10-digit number used exclusively within the Self Assessment system. It tracks your tax returns, payments, and correspondence with HMRC as a self-employed person or business owner.

You will need both if you are self-employed; your NI number is required when you register for Self Assessment, and your UTR is what you use from that point forward when filing returns and dealing with tax.

What Happens If You Do Not Get a UTR When You Should?

Failing to register for Self Assessment and obtain a UTR when required is not something HMRC takes lightly. The consequences can escalate quickly.

If you do not register by the 5 October deadline following the year you started trading, HMRC can issue a Failure to Notify penalty. This is typically a percentage of the tax owed and increases the longer you delay.

Without a UTR, you cannot file a tax return, which means missed deadlines, which trigger their own automatic fines of £100 immediately and increasing penalties the longer the return remains outstanding.

There is also the risk of interest being charged on unpaid tax that HMRC did not even know to chase, because you were never registered in the first place.

The cost of getting registered early is zero. The cost of leaving it too long can be high.

Managing Your Business Finances After Getting Your UTR

Once you have your UTR and are registered for Self Assessment, the next step is making sure your business finances are organised enough that filing your tax return each year is straightforward rather than stressful.

That means keeping clear records of your income, tracking your business expenses, issuing proper invoices to clients, and knowing what you owe before the January deadline arrives, not after.

Built For Small Business is a free platform that helps UK small business owners manage invoicing, expenses, payroll, and client records in one place, so when Self Assessment time comes around, everything you need is already organised and ready to export to your accountant.

Frequently Asked Questions

What is a UTR number?
A UTR (Unique Taxpayer Reference) is a 10-digit number issued by HMRC to identify you for Self Assessment tax purposes. It is used when filing tax returns, paying tax, and communicating with HMRC about your tax affairs.

Who needs a UTR number in the UK?
You need a UTR if you are self-employed, a sole trader, a limited company director, a business partner, a landlord, or anyone with untaxed income that needs to be declared through Self Assessment. Standard PAYE employees with no other income generally do not need one.

How do I get a UTR number?
You get a UTR automatically when you register for Self Assessment at gov.uk/register-for-self-assessment, or when you register a limited company with Companies House. HMRC sends it by post within 10 to 15 working days.

How long does it take to get a UTR number?
Around 10 to 15 working days if you are based in the UK. Up to 21 working days if you are registering from abroad.

Can I get my UTR number online or over the phone?
You can view your existing UTR online through your Personal Tax Account or the HMRC app. HMRC will not give out your UTR over the phone for security reasons if you have lost it and cannot find it online, they will post it to your registered address after verifying your identity.

Does a UTR number expire?
No. Your UTR is permanent. It stays the same for life, even if you stop trading, change address, or change your business structure.

Is a UTR number the same as a National Insurance number?
No. They are different. Your National Insurance number tracks NI contributions and benefits. Your UTR is specifically for Self Assessment and tax returns. You will need both if you are self-employed.

What happens if I do not register and get a UTR?
If you are required to register for Self Assessment and do not do so by 5 October following the year you started trading, HMRC can issue a Failure to Notify penalty. You will also be unable to file tax returns, which triggers additional fines.

Can I have more than one UTR number?
You will have one personal UTR. If you also run a limited company, the company will have its own separate UTR. A director can therefore have two UTRs, one personal, one for the company.

What is the difference between a UTR and a Company Registration Number (CRN)?
Your CRN is issued by Companies House when you register a limited company; it identifies the company as a legal entity. Your company UTR is issued by HMRC separately and is used specifically for tax purposes. They are different numbers used by different government bodies.

I am a Nigerian entrepreneur based in the UK. Do I still need a UTR?
Yes. If you are self-employed or running a business in the UK, you are subject to UK tax law regardless of your nationality. You will need to register for Self Assessment and obtain a UTR in the same way as any UK resident.

Where can I find my UTR if I have lost it?
Check HMRC correspondence, log into your Personal Tax Account at gov.uk, use the HMRC app, check old tax returns, or call HMRC on 0300 200 3310. They will post it to your registered address after identity verification.

Built For Small Business helps UK and Nigerian small business owners manage invoicing, expenses, payroll, and client records all in one free platform. If you are setting up a business in the UK,create your free account and start managing your finances properly from day one.