Understanding Your UTR: Where Can I Find My Unique Tax Reference Number?

UTR Number UK: What It Is & How to Find Yours

Your Unique Taxpayer Reference (UTR) is a 10-digit number issued by HMRC that identifies you for Self Assessment. The fastest places to find it are your SA250 “Welcome to Self Assessment” letter (top right), any previous Self Assessment tax return, the HMRC app, or your Personal Tax Account on GOV.UK. This guide explains what a UTR is, who needs one, exactly where to find yours, what to do if you cannot, and how the UTR differs from your tax code, PAYE reference and National Insurance number — the four references UK taxpayers most often confuse.

What Is a UTR Number?

A UTR is a 10-digit identifier assigned by HMRC when you register for Self Assessment, or when you incorporate a UK limited company. Once issued, it stays the same for life — even if you stop being self-employed and re-register years later.

UTRs are sometimes presented with a space in the middle, like 12345 67890, and a small minority end with the letter “K”. The K suffix is administrative and does not change the meaning of the number — if you are quoting your UTR, include the K if it appears on your HMRC paperwork.

Two types of UTR exist:

• Personal UTR — issued to an individual when they register for Self Assessment as a sole trader, landlord, company director with untaxed income, or for any other reason that takes them outside the standard PAYE system.
• Company UTR — issued to a UK limited company when it is incorporated. Companies House notifies HMRC, and HMRC posts a Corporation Tax UTR to the registered office, usually within around 14 days. Company UTRs are also 10 digits but are entirely separate from the directors’ personal UTRs.

Who Needs a UTR Number?

You need a UTR if you are required to file a Self Assessment return. This commonly applies to:

• Sole traders and self-employed individuals with profits above the trading allowance threshold.
• Partners in a business partnership.
• Company directors who receive untaxed income (such as significant dividends from their company), or whom HMRC has otherwise asked to file a return.
• Landlords with rental income above the property allowance.
• People with significant dividend, savings or investment income outside PAYE.
• Higher earners affected by the High Income Child Benefit Charge.
• Anyone selling assets that may trigger Capital Gains Tax.

If you are taxed entirely through PAYE and have no other income, you do not normally have a personal UTR and do not need one. PAYE is settled through your tax code; there is nothing for HMRC to assess separately.

Limited companies all have a Corporation Tax UTR, regardless of whether they trade. A dormant company still has one, and it is needed when filing the company tax return (CT600). Growing businesses often reach a point where fractional FD support makes this kind of compliance routine rather than reactive.

Where to Find Your UTR Number

If you have already registered for Self Assessment, your UTR will appear in several places. The order below reflects how quickly most people locate it:

1. The HMRC app

The fastest route for most people. Open the official HMRC app on your phone, sign in with your Government Gateway credentials, and your UTR is shown in the Self Assessment section. The app is available free for iOS and Android.

2. Your Personal Tax Account on GOV.UK

Sign in at gov.uk with your Government Gateway User ID and password. Your UTR is displayed under the Self Assessment area. (Note that the Government Gateway User ID is your login — your UTR is data within the account, not a credential.)

3. Your SA250 “Welcome to Self Assessment” letter

When you first registered, HMRC posted you an SA250 letter confirming the registration. The 10-digit UTR is printed at the top right of the first page. If you are abroad, this letter may have taken up to 21 working days to arrive.

4. Any previous Self Assessment tax return

Whether you filed online or on paper, your UTR will be on every previous return — usually labelled “Tax Reference” or “UTR” near the top of the form. Online copies in your HMRC account work just as well as a printed copy.

5. HMRC notices and reminders

Your UTR also appears on the annual notice to file (form SA316), Self Assessment statements of account, and any payment reminder letters HMRC sends about your tax bill.

6. Your accountant or tax adviser

If you use an accountant for Self Assessment, they will hold your UTR on file. A quick email to them is the simplest option if you cannot find your own paperwork.

How to Get a UTR Number If You Do Not Have One

If you need to file a Self Assessment return and have never had a UTR, you must register with HMRC. The standard route is online at gov.uk/register-for-self-assessment. You will need:

• Your full name, date of birth and home address.
• Your National Insurance number.
• The date you started self-employment (sole traders) or began receiving the income that requires a return.
• A Government Gateway User ID — you can create one as part of the process.

After you submit the registration, HMRC posts your UTR by letter, typically within 10 to 15 working days to a UK address (up to 21 working days if you are abroad). HMRC will also send a separate activation code for online services, which you must use within 28 days of receipt before it expires.

HMRC asks that you register within three months of the date you start self-employment, and in any case by 5 October following the end of the tax year in which you became liable to file. Missing the registration deadline can lead to a Failure to Notify penalty, calculated as a percentage of the tax owed.

What to Do If You Cannot Find Your UTR

If you have searched all the places above and still cannot locate your UTR, contact HMRC directly.

Have the following ready before you call, because HMRC will use them to verify your identity:

• Your National Insurance number.
• Your full name and date of birth.
• Your current and previous home address.
• Information from a recent payslip, P60 or other HMRC document.

HMRC will not normally read out your UTR over the phone. They will post it to your registered address as a security measure, so allow several days to receive it. Call waiting times vary considerably and are longest in the weeks before the 31 January deadline — another reason to sort a missing UTR early rather than late.

UTR vs Other UK Tax Reference Numbers

UK taxpayers regularly confuse the UTR with other reference numbers on their HMRC paperwork. They are not interchangeable, and using the wrong one when making a payment can lead to an unallocated payment and an automated late-payment notice. The table below sets out what each reference is for.

In short: if HMRC is asking who you are for Self Assessment or Corporation Tax, they want your UTR. If your employer or HR is asking you for a tax reference, they normally mean your tax code (1257L style). If you are claiming State Pension, benefits or NI credits, you will be asked for your National Insurance number.

UTR Security and What to Do If It Is Compromised

Treat your UTR like any other identifying number on your tax record. On its own, the UTR is not enough for someone to commit fraud — they would also need other identifying details — but it is regularly targeted by phishing emails and text messages claiming to be from HMRC.

Practical points:

• HMRC will never ask for your UTR by email or text message, and will never ask you to confirm it via a link. Do not click such links.
• Share your UTR only with HMRC, your accountant or another professional who genuinely needs it.
• If you suspect someone has used your UTR fraudulently, contact HMRC immediately on 0300 200 3310 and report the issue. Forward suspect emails to phishing@hmrc.gov.uk.

Frequently Asked Questions

What is a UTR number?

A Unique Taxpayer Reference (UTR) is a 10-digit identifier issued by HMRC. Individuals receive a personal UTR when they register for Self Assessment; UK limited companies receive a separate Corporation Tax UTR on incorporation. The number is permanent and stays the same throughout the taxpayer’s lifetime.

How do I find my UTR number?

Sign in to the HMRC app or your Personal Tax Account on gov.uk and look in the Self Assessment section. You will also find your UTR on the SA250 “Welcome to Self Assessment” letter, on any previous Self Assessment tax return, and on HMRC payment reminders or notices to file.

What does a UTR number look like?

It is always 10 digits long, often shown with a space in the middle — for example, 12345 67890. A small number of UTRs end with the letter “K”. It contains no other letters.

Is a tax reference number the same as a UTR?

Not necessarily. “Tax reference” is used loosely in the UK to mean different things. A UTR is one type of tax reference, used for Self Assessment and Corporation Tax. The PAYE reference on your P60 (which looks like 123/AB45678) is a different tax reference belonging to your employer’s payroll. Your tax code (1257L style) is a third. They are not interchangeable.

How long does it take to get a UTR number?

After registering for Self Assessment online, HMRC posts your UTR within about 10 to 15 working days to a UK address, or up to 21 working days if you live abroad. The activation code for online services is sent separately and must be used within 28 days.

Do I need a UTR if I am only employed under PAYE?

Usually not. If your only income is from PAYE employment and there is nothing else for HMRC to assess, you do not need to register for Self Assessment and you will not have a personal UTR. You may need one if you take on rental income, freelance work, significant dividends or any other untaxed income.

Is a company UTR the same as my personal UTR?

No. A limited company has its own Corporation Tax UTR, issued to the company at incorporation. Directors have a separate personal UTR for their own Self Assessment if HMRC requires them to file one. The two are entirely separate references and should never be used interchangeably.

Where on a Self Assessment return is the UTR shown?

On paper SA100 returns it appears in the top right of page 1. In the online HMRC service, it is shown on the Self Assessment dashboard as soon as you sign in and on the front page of any return you have started or filed.

Can I find my UTR without contacting HMRC?

In most cases yes — the HMRC app and your Personal Tax Account both display it once you are signed in, and it appears on any previous return or HMRC Self Assessment correspondence you still hold. Contacting HMRC is only necessary where you have no access to your online account and no paperwork at all.

What happens if I file a return with the wrong UTR?

The submission may fail validation, or in some cases be recorded against the wrong record entirely, which takes time to unpick. If you have used an incorrect reference on a payment rather than a return, the payment may sit unallocated and generate a late-payment notice even though the money has reached HMRC. Either situation is resolvable, but both are far easier to avoid than to correct.

Do I keep the same UTR if I stop and later restart self-employment?

Yes. The UTR is permanent. If you deregister from Self Assessment and later register again, HMRC reactivates the same reference rather than issuing a new one, so it is worth keeping a record of it even during a period when you are not filing.

References & Further Reading

• GOV.UK — Self Assessment: general enquiries
• GOV.UK — Register for Self Assessment
• GOV.UK — Find your UTR number
• ICAEW — Tax resources

This guide is general information for UK taxpayers, not tax advice. HMRC contact details and processes are correct at the time of writing — check GOV.UK for the current position before acting.

Adrian Lawrence FCA

Founder & Managing Director, FD Capital

Adrian Lawrence FCA is the founder of FD Capital and a Fellow of the Institute of Chartered Accountants in England and Wales (ICAEW). He holds a BSc from Queen Mary College, University of London, and has over 25 years of experience as a Chartered Accountant and finance leader working with private, PE-backed and owner-managed businesses across the UK.

Adrian and his network of fractional Finance Directors regularly advise founders, executives and finance teams on Self Assessment registration, Corporation Tax compliance and the everyday HMRC reference numbers — UTR, PAYE, NI — that need to be quoted correctly to keep payments and filings clean.

→ View Adrian’s ICAEW profile