UTR

Complete Guide to Unique Tax Reference Numbers

Q: 1. How many numbers are in a UTR?

Ten numbers. If there are more characters on a letter, l ook for the 10-digit core reference. GOV.UK

HMRC uses a Unique Taxpayer Reference (UTR) to match your tax records to you (or your business). It is a 10-digit number and sometimes 13 digits in certain cases. A UTR is necessary if you file a Self Assessment tax return, are self-employed, are a partner in a partnership, or run a limited company. You can’t do your Self Assessment or company Corporation Tax filings correctly without it, and you could get in trouble.

What does a UTR number mean?

HMRC gives out 10-digit UTRs as references. People use it for Self Assessment, and businesses get a different UTR for Corporation Tax. Your PAYE reference, National Insurance number, or VAT number are not the same as this. The UTR helps HMRC find the right tax record for the right person or business. GOV.UK

Who needs a UTR?

If any of the following are true, you’ll need a UTR:

● You need to file a Self Assessment return if you are self-employed (sole trader) or in a partnership. GOV.UK

● You are a person who needs to do Self Assessment because of things like having a lot of untaxed income, rental income, large capital gains, or other reasons.

● You have set up a limited company, which means that your company will get its own UTR for Corporation Tax. First Formations

Where do I look for my UTR?

HMRC will have already given you a UTR if you have registered before. Look:

● The HMRC app or your Personal Tax Account (for individuals)

● Letters from the past about Self Assessment, like “notice to file,” payment reminders, or statements

● For businesses: letters about Corporation Tax, such as the CT603 “Notice to deliver a Company Tax Return.” GOV.UK Ridge Field Consulting

If you still can’t find it, get in touch with HMRC through your online account or the links on GOV.UK and ask them to send it again.

Your UTR may appear in your Personal Tax Account or the HMRC app before the letter arrives, as HMRC moves more services online. Checking your digital account is often the fastest way to find it.

How can I get a UTR number?

You don’t apply for a UTR on its own. When you register for the right tax, HMRC sends it out automatically.

1) Self-employed people or people who file Self Assessment

●Sign up for Self Assessment online with HMRC. When you register, HMRC makes your Self Assessment record and gives you your UTR. GOV.UK

2) People who aren’t self-employed but still have to file

●If you’re not self-employed (for example, if you get rental income or certain investment gains), use the HMRC route to register for Self Assessment. As part of that process, you will get a UTR. GOV.UK

3) Companies that are limited

●Companies House tells HMRC when you set up a business. HMRC then sends the registered office a company UTR by mail. This is used for the CT600 return and Corporation Tax.

How long does it take?

In the UK, HMRC usually sends or re-sends a UTR by mail within about 10 working days for UK addresses (often 15 days by post) and potentially longer for overseas recipients. It may take longer if you are outside the UK. You might be able to see it in your online account or HMRC app sooner in some cases. During busy times, timelines can change.

Tip: HMRC is moving more services online, and some helplines are only open for a few hours or close for the season. So, online self-service is usually the quickest way to get help. The Guardian.

What if I can’t find my UTR?

Look through your HMRC papers (letters, notices to file, payment reminders) and check your Personal Tax Account or HMRC app.
If you still can’t find it, ask for it on GOV.UK (HMRC will send it safely).

Important: keep your UTR safe like any other private ID. It’s not a password, but it is linked to your tax record, so keep it safe and private.

Do I need a UTR to file my return?

Yes. To file your own Self Assessment or a Company Tax Return, you will need a valid UTR. If you submit without a UTR, it will fail and you could miss deadlines and get fines. GOV.UK

Personal UTR vs. Company UTR (and other sources)

Identifier	Who uses it	What it’s for	Where you find it	Format
UTR (individual)	Individuals/sole traders	Self Assessment returns & correspondence	Personal Tax Account, HMRC app, Self Assessment letters	10 digits
UTR (Company)	Limited companies	Corporation Tax (CT600), CT correspondence	Company tax letters (e.g., CT603), registered office mail	10 digits
National Insurance (NI) no.	Individuals	National Insurance, benefits, PAYE identification	NI letters/card, payslips, P60	2 letters + 6 digits + letter (e.g., AB123456C)
PAYE refrence	Employers/employees	Employee tax under PAYE, payroll filings	Employer payslips, P45/P60, employer correspondence	3 digits/letter + reference 3 digits (HMRC office number) / employer reference (e.g., 123/AB45678)
VAT number (if registered)	VAT-registered businesses	VAT returns & invoices	VAT registration certificate, VAT letters	9 digits (GB…) 9 digits (usually starts with GB, e.g., GB123456789)

HMRC gives details about UTR and where to find them. CT603 is the company’s “notice to deliver a Company Tax Return.” ct603 GOV.UK

Step by step: Registering to get your UTR

Sole Traders And Individuals

Make sure you need to file Self Assessment (GOV.UK guide).

You can sign up for Self Assessment online by making an account on Government Gateway.

Wait for your UTR to come in the mail or see it online sooner.

When you receive your activation code, link the service in your account and complete your return by the deadlines. GOV.UK

For small businesses

● Register with Companies House.

● HMRC sends the UTR for your business to the registered office.

● Use it to sign up for Corporation Tax and file the CT600 by the due dates set by law. The CT603 notice will be sent out by HMRC if they need a return. 1st Formations Ridge Field Consulting

Common mistakes (and how to avoid them)

● Taking too long to sign up: You might not get your UTR in time if you wait until just before the filing or payment deadlines to register. Sign up early. GOV.UK

● Identifiers that don’t make sense: Your UTR is not the same as your National Insurance number or PAYE reference. Use the right one on the right forms.

● Only using the phone: HMRC’s phone support may not be available all the time, but online self-service is usually faster. The Guardian

● Moving and not getting HMRC mail: To get your UTR letters, make sure to update your address with HMRC and Companies House (for businesses).

● Don’t give out your UTR to just anyone; only to people you trust, like your accountant.

A quick list

● Do you need to file your Self Assessment? Sign up online and let HMRC give you your UTR. GOV.UK

● Can’t find your UTR? If you don’t see it, check the HMRC app, your Personal Tax Account, and any letters you got before. If you still don’t see it, ask GOV.UK to send it again. GOV.UK

● Do you own a business? After you register your business, you should get a company UTR in the mail. You can use this to handle Corporation Tax. 1st Formations

How Taxaccolega can help you

● Taxaccolega makes sure that your filings are correct and on time by registering clients correctly, getting missing references, setting up your HMRC online services, and preparing your returns from start to finish. We’ll help you figure out if you need Self Assessment or if you’ve started a new business and haven’t seen the CT603/UTR yet.