How Do I Get My UTR Number? New, Lost and Company UTRs Explained

Your Unique Taxpayer Reference (UTR) is the ten-digit number HMRC uses to match you to your Self Assessment record. You cannot file a return without it. You also cannot simply ask HMRC for one on its own: the UTR is issued as part of registering.

The number comes by post, not on screen. Leave registration until a deadline is close and you can end up waiting for the letter while the clock runs. This guide sets out the right route for your situation, how long each takes, and the mistakes that cause delays.

Last reviewed: [September 2026]

How do I get my UTR number?

If you have never had a UTR, register for Self Assessment on GOV.UK. HMRC sets up your record and usually posts your UTR within 15 working days, or 21 days if you live abroad. If you already have one, it is in your Personal Tax Account, the HMRC app and on past HMRC letters.

There is no separate UTR application form for individuals. Registering for Self Assessment is the application. Once HMRC processes it, the UTR is created and posted to the address you gave.

On some HMRC letters the UTR is labelled simply “tax reference”. It is not your National Insurance number, and it is not the PAYE reference on your payslip or P60. HMRC will not accept either in place of a UTR on a Self Assessment return.

Which situation are you in?

Find the row that fits you, then go to the matching section below.

Your situation	What to do	What to expect
Self-employed or sole trader for the first time	Register for Self Assessment through the self-employed route on GOV.UK	UTR usually by post within 15 working days
Not self-employed but need to file (for example, rental or other untaxed income)	Register through the route for people who are not self-employed	Same postal timing
Registered in the past but stopped filing	Reactivate your Self Assessment account instead of registering as new	GOV.UK takes you through reactivation within the registration service
Have a UTR but cannot find it	Check your Personal Tax Account, the HMRC app, and old returns or HMRC letters	If none of these work, contact HMRC
Run a limited company	Request the company’s Corporation Tax UTR online	Posted to the registered office address held by Companies House
In a partnership	The nominated partner registers the partnership; each partner also registers individually	Only the nominated partner can register online as a partner; other partners register by post

Some people fit more than one row. A sole trader who becomes a company director, for example, holds two UTRs: a personal one for Self Assessment and one for the company’s Corporation Tax. Putting the company UTR on a personal return is one of the most common filing errors.

Getting a UTR for the first time

If HMRC has never issued you a UTR, you get one by registering for Self Assessment. The route depends on why you need to file, so check that first.

Who needs a UTR

You need a UTR if you have to send a Self Assessment tax return. HMRC says you must send one for a tax year (6 April to 5 April) if any of these applied:

You were self-employed as a sole trader and earned more than £1,000 before deducting anything you can claim tax relief on.
You were a partner in a business partnership.
You had Capital Gains Tax to pay on something you sold or disposed of.
You had to pay the High Income Child Benefit Charge.

You may also need to file if you had untaxed income, such as rent from property, tips and commission, savings and investment income, dividends or foreign income. If you are unsure, use HMRC’s check if you need to send a tax return tool before registering.

Some people register voluntarily, for example to claim certain Income Tax reliefs, to prove self-employment for Tax-Free Childcare or Maternity Allowance, or to pay voluntary National Insurance. A UTR is issued in these cases too.

Note: Being employed does not rule you out. Many people on PAYE need a UTR because of a side business, rental income or the High Income Child Benefit Charge.

What you need before you register

Gather these first. Most stalled registrations stall because something on this list was missing halfway through.

Your National Insurance number (if you have one)
Your full name, date of birth, postal address and daytime phone number
If self-employed: the date you started trading, what the business does, and the business address and phone number if different from your own
If not self-employed: the reason you need to file and the date it started
HMRC sign-in details, which you can create during registration if you do not have them

The start date matters more than people expect. It tells HMRC which tax year your first return covers, which sets your notification deadline. Use the date you actually started trading or receiving the income, not the date you registered.

Registering online, step by step

Go to Check how to register for Self Assessment on GOV.UK and answer the questions. The service routes you to the self-employed, not self-employed or partnership registration.
Sign in, or create sign-in details when prompted.
Enter your personal details and National Insurance number.
Add your business details and start date, or explain why you need to file and when that started.
Check the summary before submitting, especially your postal address, because your UTR is sent there.
Keep a note or screenshot of the confirmation in case you need to chase HMRC later.

If the service says you are already registered, stop. Do not register again under slightly different details. You most likely have an existing UTR or a dormant record to reactivate, both covered below.

Registering by post

If you cannot use the online service, you can register on paper. People who are not self-employed use form SA1, which can be filled in, printed and posted. Partnerships use form SA400, and individual partners use form SA401. Postal routes are slower, so avoid them when a deadline is close.

HMRC’s Self Assessment helpline can talk you through registration or confirm whether you are already on its system. Check the current number and opening hours on GOV.UK’s HMRC contact page rather than relying on a number copied from another website.

How long does it take to get a UTR?

GOV.UK says you will usually get your UTR by post within 15 working days of registering, or 21 days if you live abroad. It can take longer in busy periods. If you registered online, you may be able to see it sooner in the HMRC app or your Personal Tax Account.

Plan around that wait. People who register a week before filing their first return are the ones who get stuck.

UK vs overseas timing

Where you live	UTR by post	Activation code (if needed)
UK	Usually within 15 working days	Usually within 7 working days
Abroad	Usually within 21 days	Usually within 21 days

These are HMRC’s published timescales, not guarantees. The run-up to the October and January deadlines can stretch them. If nothing has arrived, check when you can expect a reply from HMRC before calling.

Why the UTR and activation code arrive separately

Two letters can be involved, and they do different jobs.

The UTR letter confirms you are registered and gives you your ten-digit reference.
The activation code is a separate 12-digit code. You use it the first time you sign in to activate Self Assessment online, so you can file.

Activation codes expire, so use yours as soon as it arrives. If it is lost or out of date, sign in to HMRC online services and request a replacement. The replacement takes the same posting time as the original, so a lost code a few days before 31 January is a real problem.

Illustrative example: a new sole trader’s timeline

Illustrative example. Assumptions: fictional person, UK resident, self-employed only.

Amira starts a mobile dog-grooming business on 1 November 2026, in the 2026/27 tax year. Her takings are clearly above £1,000, so she needs to file.

15 November 2026: she registers online as self-employed, giving 1 November as her start date.
Late November 2026: her activation code arrives, usually within 7 working days. She signs in and activates Self Assessment.
Early December 2026: her UTR letter arrives, within about 15 working days of registering.
Deadlines met with room to spare: she has told HMRC well before 5 October 2027, the notification deadline for a first return covering 2026/27. Her online return and any tax due follow by 31 January 2028.

Had Amira waited until late September 2027, registering before 5 October would still meet the deadline. But her UTR and code would then arrive in the busiest season, with far less room if anything went missing in the post.

The 5 October requirement is to tell HMRC, and you do that by registering. You do not need the UTR in your hand by that date. A UTR arriving late does not make you late; registering late does.

The registration deadline many guides get wrong

If you need to file a tax return for the first time, you must tell HMRC by 5 October after the end of that tax year, and you do it by registering. Miss the date and you could face a penalty, even though the return itself is not due until 31 January.

Some websites still say you must register “within three months of starting your business”. That is not the test for Self Assessment. The three-month rule belongs to Corporation Tax registration for limited companies, covered further down.

Who the 5 October deadline applies to

It applies if you need to file for the previous tax year and either:

you have never sent a Self Assessment return before, or
you registered in the past but did not need to send a return for the tax year before that one.

The second point catches returning taxpayers. If you filed years ago, stopped, and now have new income, you need to notify HMRC again, usually by reactivating your existing account.

Key dates by tax year

Tax year	Runs	Tell HMRC (register) by	Online return and payment due
2025/26	6 April 2025 to 5 April 2026	5 October 2026	31 January 2027
2026/27	6 April 2026 to 5 April 2027	5 October 2027	31 January 2028

If you started self-employment or received new untaxed income in 2025/26 and have not registered yet, 5 October 2026 is your date. Register now. You do not need your UTR by then; submitting the registration is what counts.

What happens if you register late

Registering after 5 October does not automatically mean a fine. It opens you to a failure to notify penalty, and the amount depends on three things:

The tax left unpaid because of the late notice. HMRC calls this the potential lost revenue. The penalty is a percentage of it, not a fixed sum.
Your behaviour. A genuine oversight is treated very differently from a deliberate failure, and a deliberate, concealed one more harshly still.
How the failure comes to light. Telling HMRC yourself, before it contacts you, earns a larger reduction. So does helping HMRC work out the figures and giving access to your records.

Because the penalty is tied to unpaid tax, someone who meets the filing criteria but owes no tax cannot be charged a failure to notify penalty for registering late. And someone who registers a few weeks late but files and pays in full by 31 January usually has far less exposure than someone who also misses the payment date.

If the failure was not deliberate and you had a reasonable excuse, HMRC will not charge the penalty. HMRC’s factsheet CC/FS11 explains how these penalties are calculated and reduced.

None of this is a reason to delay. Late registration squeezes the time you have to receive your UTR, activate online access and prepare the return.

Note: Making Tax Digital for Income Tax works differently from standard Self Assessment. If you are within its scope, check the separate GOV.UK sign-up guidance too.

How to find a UTR you already have

If you have registered before, your UTR has not gone anywhere. It is shown in your Personal Tax Account and the HMRC app, and printed on past returns and most HMRC letters. Contact HMRC only once you have checked all of these.

A UTR is issued once and stays with your Self Assessment record. Losing the letter does not mean applying for a new one. You track down the one you have. GOV.UK’s Find your UTR number page sets out the official options.

Personal Tax Account

Usually the fastest route if you can already sign in. Sign in to your Personal Tax Account on GOV.UK and open the Self Assessment section, where your UTR is shown.

Forgotten your sign-in details? Use the recovery options on the sign-in page. Do not create a second account: a fresh one is not linked to your Self Assessment record, so your UTR will not appear in it.

HMRC app

The HMRC app shows your UTR once you have signed in and verified your identity. It is handy when a contractor or adviser asks for the number while you are away from your desk.

Old returns and HMRC letters

Your UTR appears on:

copies of previous Self Assessment returns
notices to file a return
payment reminders and statements

It may be labelled “tax reference” rather than “UTR”. Look for a ten-digit number, often in two blocks of five. Your National Insurance number mixes letters and numbers, so it is easy to tell apart. Your P60 will not help: it shows your employer’s PAYE reference instead.

If an accountant has filed for you before, they will have your UTR on file, and asking them is often quicker than waiting for HMRC.

When to contact HMRC

If you cannot find your UTR online or on any HMRC document, contact HMRC. Expect security questions before an adviser discusses your record. Have your National Insurance number, address and recent tax details to hand, and check GOV.UK’s HMRC contact page for the right helpline and hours.

For an organisation’s UTR, such as a partnership or trust, check its previous returns and HMRC letters first, then contact HMRC. Limited companies have a quicker option, covered in the company UTR section.

Keep your UTR safe. Give it only to people who need it, such as your accountant or a contractor under CIS. Be wary of unexpected texts, emails or calls asking for it, and go to GOV.UK directly rather than following links in messages.

Registered before but stopped filing? Reactivating your account

If you have been in Self Assessment before but did not send a return last year, you usually do not register again. You reactivate your existing account, by the same 5 October deadline that applies to new registrations.

Most guides skip this route, and it causes many duplicate records. Someone who filed five years ago and now has new income often goes through the full new-registration process, which confuses HMRC’s records and delays everything.

When reactivation applies

You probably need reactivation if any of these fit:

You were self-employed before, closed that business, and have started trading again.
You filed because of rental or other income, stopped when it ended, and now have a new reason to file.
HMRC took you out of Self Assessment because PAYE covered everything, but you now have untaxed income or the High Income Child Benefit Charge.
You filed as a partner in a partnership that has ended, and now have income of your own to declare.

In each case a Self Assessment record already exists in your name; it is dormant. Reactivation brings it back into use, and you normally carry on using your existing UTR.

How to reactivate

Find your existing UTR if you can, using the section above.
Go to Check how to register for Self Assessment and answer honestly that you have registered before. The service takes you through reactivation instead of new registration.
Give details of the new income: for self-employment, the new start date and what the business does.
Sign in afterwards and check that Self Assessment shows as active before you try to file.

Reactivate before you start preparing the return, not at the point of submission. If your online access also lapsed, you may need an activation code by post, which is the same wait a new registrant faces.

Illustrative example

Illustrative example. Assumptions: fictional person, figures for illustration only.

Daniel filed returns as a self-employed plumber until he took a salaried job in 2021, then told HMRC he no longer needed to file. In 2025/26 he began letting out a flat. Rather than registering as new, he reactivates his old record before 5 October 2026, giving details of the rental income. He then reports it on his 2025/26 return under his existing UTR.

The reverse: you no longer need to file

If you stop being self-employed, or your reason for filing ends, tell HMRC you no longer need to send a return. Until you do, HMRC may keep expecting one. If HMRC has already sent you a notice to file for a year, you must file by the deadline on that notice. Speak to HMRC rather than ignoring it.

How to get a company UTR

A limited company does not apply for a UTR the way an individual does. HMRC issues one after the company is incorporated at Companies House and posts it to the company address. If it never arrived or was lost, you can request it online, and HMRC posts it to the registered office address held by Companies House.

The company UTR is separate from any personal UTR you hold as a director or sole trader. It is for Corporation Tax, not Self Assessment. A director who also files a personal return holds two UTRs, and each belongs on its own return.

When the company UTR arrives

HMRC posts the company UTR shortly after incorporation. Watch where it goes: if your registered office is a formation agent’s or accountant’s address, the letter lands with them. Ask them to forward HMRC post promptly.

The UTR is not the same as being registered for Corporation Tax

Receiving the UTR letter does not set the company up for Corporation Tax. Once the company starts to do business, which includes buying, selling, advertising, renting property or employing someone, you must register it for Corporation Tax within three months. You need the company UTR to do so, and a late registration can bring a penalty.

That three-month rule belongs to Corporation Tax. It is probably why “three months” gets wrongly repeated in guidance about personal UTRs, where the real test is the 5 October deadline.

If the company UTR is lost or never arrived

Check HMRC letters sent to the registered office, including anything a formation agent or previous accountant received.
If the company is set up in HMRC online services, sign in: the UTR is shown there.
If neither works, use GOV.UK’s Find your UTR number page to request the Corporation Tax UTR online. HMRC posts it to the registered office on the Companies House register.

Because the replacement goes only to that registered address, make sure it is up to date before you request it.

Company UTR vs Company Registration Number

CRN: issued by Companies House, usually eight characters, sometimes starting with letters.
Company UTR: issued by HMRC, always ten digits.

HMRC will not accept the CRN where it asks for a UTR.

UTR vs NI number vs CRN vs PAYE reference

A UTR is the ten-digit number HMRC uses for Self Assessment or Corporation Tax. It is not your National Insurance number, your company’s registration number, your employer’s PAYE reference or your tax code. Using the wrong one is a common cause of rejected forms and misallocated payments.

Number	Issued by	What it looks like	Used for	Where you find it
Personal UTR	HMRC	10 digits	Your Self Assessment record	Personal Tax Account, HMRC app, past returns, HMRC letters
Self Assessment payment reference	HMRC	Your 10-digit UTR followed by the letter K	Paying your Self Assessment bill	HMRC online account or paying-in slip
Company UTR	HMRC	10 digits	The company’s Corporation Tax record	HMRC letter to the company, HMRC online services
National Insurance number	Government	A mix of letters and numbers	National Insurance and your wider tax record	Payslips, P60, Personal Tax Account
Company Registration Number (CRN)	Companies House	Usually 8 characters, sometimes starting with letters	Identifying the company on the public register	Certificate of incorporation, Companies House register
Employer PAYE reference	HMRC, to employers	A tax office number and reference	Your employer’s payroll scheme	Payslips, P60, P45
Tax code	HMRC	Numbers and a letter	Telling an employer or pension provider how much tax to deduct	Payslips, P60, Personal Tax Account

Mix-ups we see most often

Paying with the UTR alone. Self Assessment payments need the 11-character reference: your UTR plus K. A wrong reference can delay your payment reaching your account.
Giving a contractor your NI number instead of your UTR. Under CIS, contractors need your UTR to verify you. If they cannot verify you, or you are not registered for CIS, they must deduct 30% instead of the standard 20%.
Entering the CRN where the company UTR belongs. Both appear on early company paperwork. Only the ten-digit HMRC number is the UTR.
Assuming PAYE paperwork shows a UTR. Payslips and P60s show your employer’s PAYE reference and your tax code. Employees who have never been in Self Assessment do not have a UTR.

Common mistakes when getting a UTR

Most UTR problems come from timing, duplicate registrations and wrong details, not from HMRC losing paperwork.

Leaving registration until the return is due. By January the 5 October notification date has passed, and the UTR and activation code still take weeks to arrive. Register as soon as you know you will need to file.
Registering twice. If the service says you already have a record, believe it. Re-registering with a different spelling or an old address can leave HMRC with two records for one person.
Creating a new sign-in instead of recovering the old one. A new account is not linked to your existing Self Assessment record, so your UTR will not show. Use the recovery options on the sign-in page.
Using the wrong start date. Use the date you actually began trading or receiving the income, not the date you registered or opened a bank account. It decides which tax year your first return covers.
Giving an address you are about to leave. The UTR and activation code go to the address you register with. For a company, they go to the registered office on the Companies House register.
Registering as new when you should reactivate. Returning taxpayers usually reactivate their existing record. Starting again is the most common cause of duplicate records.
Thinking the UTR means you are ready to file. The UTR confirms registration. You may still need to activate Self Assessment online with an activation code, and a company still has to register for Corporation Tax.
Ignoring HMRC because you think you owe nothing. If you must send a return, or HMRC has asked for one, you can be penalised for not filing even when no tax is due. If you genuinely do not need to file, tell HMRC.

One more caution: register through GOV.UK’s own service or an accountant you have chosen. Be wary of websites offering to “get your UTR” for a fee, and never share your HMRC sign-in details with them.

What happens after your UTR arrives

The UTR letter is the start, not the end. Activate online access, keep records from your start date, note your deadlines, and if you are a sole trader or landlord, check whether Making Tax Digital will apply.

Activate online access

Sign in to HMRC online services and check that Self Assessment shows as active. If you were sent an activation code, enter it as soon as it arrives, because codes expire. Only then can you file online, or have an accountant you authorise file for you.

Keep the number safe and to hand

Store the letter with your tax papers. You will need the UTR for every return and payment, and accountants, mortgage lenders and CIS contractors often ask for it. Share it only with people who genuinely need it.

Keep records from day one

Your first return covers income from your start date, not from when the UTR arrived. Keep sales records, receipts, bank statements and mileage logs from the beginning. Rebuilding months of records in January is where most first-year errors start.

Pay with the right reference

When you pay a Self Assessment bill, the reference is your 10-digit UTR followed by the letter K. Using the wrong reference can delay your payment reaching your account.

Check whether Making Tax Digital applies

Making Tax Digital for Income Tax is being phased in for sole traders and landlords based on qualifying income, meaning gross income from UK self-employment and UK property before expenses. Current GOV.UK guidance:

Qualifying income over	In tax year	Must use MTD for Income Tax from
£50,000	2024/25	6 April 2026
£30,000	2025/26	6 April 2027
£20,000	2026/27	6 April 2028

For a first-time registrant the key point is this: GOV.UK says you do not need to start using MTD for Income Tax until after you have submitted your first Self Assessment return, though you can sign up early. Your first return is filed in the normal way, and MTD matters from then on if your income passes the threshold.

If you would rather not handle this yourself

Some people are happy to register and file alone. Others would rather hand over the whole thing: registration, online access, records and the return itself. That is especially true in the first year, with more than one income source, or with an MTD start date to plan for.

If that sounds like you, speak to Major Accountancy about [INSERT VERIFIED SERVICE, e.g. Self Assessment registration and tax return support]. We can check which route applies, register you correctly the first time, and take the filing off your plate.

Frequently asked questions

Can I get my UTR number online instantly?

Not usually. HMRC normally posts it within 15 working days of registering. If you registered online, you may be able to see it sooner in the HMRC app or your Personal Tax Account. If you already have a UTR, both show it straight away.

Can I get my UTR number over the phone?

If you have a UTR but cannot find it anywhere, HMRC’s Self Assessment helpline can help once you pass its security checks. Check GOV.UK for the current number and hours. If you have never registered, the helpline cannot issue a UTR on the spot; you still need to register.

Does my UTR ever change?

Your personal UTR stays with your Self Assessment record. Losing the letter does not get you a new number, and if you stop filing and come back, you normally reactivate the same record. A limited company has its own separate UTR.

Do I need a UTR to work under CIS?

Yes. You need a UTR to register as a CIS subcontractor, and contractors use it to verify you. If you have no UTR, register for Self Assessment as a new business and choose “working as a subcontractor”; HMRC registers you for Self Assessment and CIS together. Unregistered or unverified subcontractors have 30% deducted instead of 20%.

Is my UTR the same as my tax code?

No. Your tax code tells an employer or pension provider how much tax to deduct through PAYE. Your UTR identifies your Self Assessment record. Many employees have a tax code but no UTR.

Can an accountant get my UTR for me?

An accountant acting as your agent can register you for Self Assessment through HMRC’s agent services and, once authorised, help track down an existing UTR. You still need to give them accurate details, including your National Insurance number and income start date.

What if I live outside the UK?

You can still register if you need to file, for example because of UK rental income. Your postal address can be outside the UK. Allow extra time: HMRC says the UTR usually takes up to 21 days to arrive abroad, and the activation code up to 21 days too.

Sources

Author: [September 2026]
Reviewed by: Shamayun Chowdhury, Senior Accountant, Major Accountancy

How Do I Get My UTR Number? New, Lost & Company UTRs