You cannot apply for a UTR number on its own. HMRC issues one automatically when you register for Self Assessment, and which registration route you use depends on why you need a tax return. It usually arrives by post within 15 working days, or 21 days if you are abroad, but it appears sooner in the HMRC app and your personal tax account. A limited company gets its own separate UTR when it is incorporated.
The thing most people get wrong is treating this as an application. There is no UTR form. You register for the tax, and the reference follows.
All details were checked against GOV.UK on 2 October 2026.
What a UTR number is
A Unique Taxpayer Reference is a 10-digit number HMRC uses to identify you as a taxpayer. It is sometimes referred to as a “tax reference”.
Your UTR stays with you for life. You do not get a new one if you change job, start a second business or stop trading and start again years later.
You need it to file a Self Assessment return, to register for the Construction Industry Scheme, and to give to an accountant acting for you. When you pay a Self Assessment bill, your payment reference is eleven characters: your 10-digit UTR followed by the letter K. Using the wrong reference can delay the payment or have it applied to a different tax bill.
How to get one: the three routes
GOV.UK no longer has a single registration page. You will be asked why you need to send a tax return, and be sent down one of three routes. Picking the wrong one is the most common cause of delay.
Why you need a return
What you register for
Form, if you cannot register online
You are self-employed as a sole trader
Self Assessment and Class 2 National Insurance
CWF1
You are a partner in a business partnership
Self Assessment and Class 2 National Insurance
SA401, and the nominated partner registers the partnership on SA400
Any other reason, such as rental or pension income
Self Assessment only
SA1
If you are self-employed
This is the route for sole traders. You register for Self Assessment and Class 2 National Insurance together, which is why it uses a different form from everyone else.
If you are registering as a CIS subcontractor, choose “working as a subcontractor” during this process. That registers you for Self Assessment and CIS at the same time, which solves a problem described below.
If you are a partner in a partnership
Two registrations are needed, not one. Each individual partner registers themselves using SA401, and the nominated partner separately registers the partnership itself using SA400. A partner that is not an individual, such as a company or a trust, uses SA402.
The partnership gets its own UTR, and so does each partner.
If you need a tax return for another reason
Rental income, untaxed income, high income, foreign income and several other situations require a return without you being self-employed. This route registers you for Self Assessment only, with no Class 2 National Insurance, and uses SA1.
What you need before you start
You sign in to register. If you do not already have sign-in details you can create them during the process. HMRC now uses two credential types: a Government Gateway user ID, or a GOV.UK One Login with an email address and password.
Have to hand your name, date of birth, address, National Insurance number, and the date you started trading if you are self-employed.
How long it takes
What
How long
UTR by post, in the UK
Usually 15 working days
UTR by post, if you are abroad
21 days
In the HMRC app or personal tax account
Sooner than the post
Activation code for the online account
A further 7 working days, or 21 if abroad
HMRC says these can take longer during busy periods, and it publishes a live tool for checking current waiting times rather than committing to a fixed figure.
Check the app before you assume it has not arrived. GOV.UK states plainly that you get the number sooner in the HMRC app or your personal tax account than by post. A lot of people wait for a letter that is slower than what is likely already on their mobile device.
Build the waiting time into your planning. If you register in mid-January hoping to file by the 31st, the UTR and then the activation code may not arrive in time.
The deadline and what happens if you miss it
You must tell HMRC by 5 October following the end of the tax year in which the income arose. For the tax year that ended on 5 April 2026, that deadline is 5 October 2026.
This applies if you have not sent a tax return before, or if you registered previously but did not need to send one for the preceding year.
Registering late does not remove the obligation. HMRC will write to you with a new filing deadline, three months from the date of that letter. The payment deadline does not move. Tax owed for the year ended 5 April 2026 is still due by 31 January 2027.
The penalty for registering late
Failing to tell HMRC on time can bring a failure to notify penalty, charged as a percentage of the tax still outstanding.
Behaviour
Disclosure
Penalty
Non-deliberate
Unprompted, within 12 months of the tax being due
0% to 30%
Non-deliberate
Unprompted, 12 months or more after
10% to 30%
Non-deliberate
Prompted
10% to 30%
Deliberate
Unprompted
20% to 70%
Deliberate
Prompted
35% to 70%
Deliberate and concealed
Unprompted
30% to 100%
Deliberate and concealed
Prompted
50% to 100%
Telling HMRC before they come to you is worth a great deal, because an unprompted disclosure attracts a lower band than a prompted one, and a non-deliberate unprompted disclosure made within 12 months can attract no penalty at all. And HMRC does not charge a penalty for a non-deliberate failure where there is a reasonable excuse.
The penalty is charged on the tax left unpaid, so registering late and paying on time limits the exposure.
Company UTRs are different
A limited company has its own UTR, separate from the personal UTR of anyone who runs it. A director who is also a sole trader will hold two.
You do not apply for it. Registering the company at Companies House usually sets it up for corporation tax at the same time, and HMRC posts the UTR to the registered office address, so check that address is right before you incorporate.
If it has not arrived 15 working days after registering the company, you can request it online. That online request service exists for corporation tax UTRs only, not for personal ones.
How to find a UTR you have lost
For an individual or sole trader, in rough order of speed:
The HMRC app. The quickest route.
Your personal tax account on GOV.UK.
Previous tax returns, notices to file, payment reminders and other HMRC correspondence.
Contact HMRC if none of those work.
For a limited company, you can request the corporation tax UTR online and HMRC will send it to the registered office address.
There is no online “request a UTR” service for individuals. If you cannot find yours through the app, your tax account or your paperwork, the remaining route is the Self Assessment helpline.
When you do not need one
The trading allowance is £1,000 a year. If your gross trading income is £1,000 or less you do not normally need to tell HMRC or register for Self Assessment, and you will not be issued a UTR.
Note that this is gross income, not profit, and that there are exceptions. You must register if you cannot use the allowance, or if you need to send a return for another reason. Other income above £1,000 but under £2,500 means contacting HMRC rather than registering; other income over £2,500 means registering.
UTRs and Making Tax Digital
Making Tax Digital for Income Tax began on 6 April 2026 for people with qualifying income over £50,000.
To sign up you must already be registered for Self Assessment and have submitted a return in the last two years, and you use the same sign-in details you got when you registered. So the UTR comes first, not the other way round.
HMRC began signing people up automatically in September 2026 where they need to use Making Tax Digital for 2026/27 and have not signed themselves up.
You may be asked for further proof of identity when using the service, either by matching a photo of your face to a passport or driving licence, or by answering questions about information HMRC already holds.
Frequently asked questions
How do I apply for a UTR number?
You do not apply for one directly. You register for Self Assessment, and HMRC issues the UTR as part of that process. Which route you use depends on why you need a tax return: sole traders register for Self Assessment and Class 2 National Insurance together, partners use a separate route, and anyone needing a return for another reason uses a third.
How long does it take to get a UTR number?
Usually 15 working days by post in the UK, or 21 days if you are abroad, and longer during busy periods. It appears sooner in the HMRC app and your personal tax account, so check there before assuming it has been lost.
What does a UTR number look like?
It is a 10-digit number. When paying a Self Assessment bill the reference is 11 characters: the 10 digits followed by the letter K.
What is the deadline to register for Self Assessment?
5 October following the end of the tax year in which the income arose. For the tax year ended 5 April 2026 the deadline is 5 October 2026. Registering after it does not change the date the tax is due.
What happens if I register late?
HMRC gives you a new filing deadline three months from the date of their letter, but the payment deadline is unchanged. You may also get a failure to notify penalty, charged as a percentage of the tax still outstanding, with lower bands where you come forward yourself rather than waiting to be contacted.
Do I need a UTR to register for CIS?
Yes. Registering for the Construction Industry Scheme online requires a UTR you already hold. If you do not have one, register as a new business for Self Assessment and select “working as a subcontractor”, which registers you for both at once. Registered subcontractors have 20% deducted from payments rather than 30%.
Can I find my UTR online?
Yes, in the HMRC app or your personal tax account. Both are faster than waiting for post. For a limited company you can request the corporation tax UTR online, but there is no equivalent online request service for an individual’s UTR.
Is a company UTR the same as my personal one?
No. A limited company is issued its own UTR when it is incorporated, posted to the registered office address. Someone who runs a company and also trades as a sole trader will hold two separate references.
