If you are new to self-employment, have just become a company director, or have received a letter from HMRC asking you to file a tax return, one of the first things you will hear about is a UTR number. You need it to file your tax return, access your HMRC online account, and communicate with HMRC about your tax affairs.
This guide explains exactly what a UTR number is, how to get one, how long it takes, where to find it if you already have one, and what to do if you have lost it.
What Is a UTR Number?
UTR stands for Unique Taxpayer Reference. It is a 10-digit reference number issued by HMRC when you register for Self Assessment or Corporation Tax. It is unique to you (or your company) and does not change – once issued, your UTR stays with you for life.
Your UTR is used:
- To file your Self Assessment tax return (sole traders and individuals)
- To access your HMRC online account
- To correspond with HMRC about your personal tax affairs
- By your accountant when they communicate with HMRC on your behalf
A UTR looks like this: 1234567890 (ten digits, no letters).
Personal UTR vs Company UTR – What’s the Difference?
Personal UTR (Self Assessment UTR): Issued to individuals when they register for Self Assessment. Used for personal income tax returns, Self Assessment, Capital Gains, and related personal tax matters.
Company UTR (Corporation Tax UTR): Issued to a limited company when it is registered at Companies House. Used for Corporation Tax returns, company tax affairs, and HMRC correspondence relating to the company.
If you are a director of your own limited company, you will have two separate UTRs:
- Your personal UTR (for your own Self Assessment return)
- Your company’s UTR (for the company’s Corporation Tax return)
These must never be confused. Filing a personal return using the company UTR – or vice versa – causes significant administrative problems with HMRC.
How to Get a UTR Number
You obtain a UTR number by registering with HMRC for the appropriate tax type:
If you are self-employed (sole trader): Register via form CWF1 online at gov.uk. As part of registering for Self Assessment, HMRC will issue you a personal UTR.
If you are a director (not self-employed): Register via form SA1 online at gov.uk.
If you need to file a Self Assessment return for another reason (rental income, capital gains, foreign income, income over £100,000): Register via form SA1 online at gov.uk.
If you are registering a limited company: When you incorporate at Companies House, HMRC is automatically notified. Within a few weeks, HMRC will write to your company’s registered address with the company’s UTR.
After registering, how long does a UTR take to arrive?
HMRC posts UTR numbers to your registered address by second-class letter. Allow:
- Standard processing: 10–15 working days
- Busy periods (October–January): up to 21 working days
There is no way to receive your UTR faster – HMRC does not issue UTRs by email or phone. This is why registering well before the 5 October deadline is so important.
Where to Find Your UTR If You Already Have One
If you have previously registered for Self Assessment, your UTR is in several places:
HMRC correspondence: Any letter, P800, or SA302 you have received from HMRC will show your UTR in the top right corner or at the top of the document.
HMRC online account (Personal Tax Account): Log in at gov.uk/personal-tax-account. Your UTR is displayed under “Self Assessment” in your account.
HMRC Self Assessment return: Any previously filed SA100 will show your UTR on the first page.
Previous tax return software: If you have filed previously using commercial software (Xero, FreeAgent, GoSimpleTax), your UTR will be stored in the system.
Your accountant: If you use an accountant who is registered as your agent with HMRC, they will have your UTR on file.
What to Do If You Have Lost Your UTR Number
If you cannot find your UTR and cannot access your HMRC online account, here is what to do:
Option 1: HMRC online (Self Service) Log into your HMRC online account at gov.uk and navigate to Personal Tax Account → Self Assessment. Your UTR will be displayed there.
Option 2: HMRC Phone Call the HMRC Self Assessment helpline: 0300 200 3310. Have your National Insurance number and date of birth ready to verify your identity. HMRC can tell you your UTR verbally and arrange for it to be sent to your registered address.
Option 3: Your accountant If you use an accountant, call them – they will have your UTR on their systems.
Option 4: Government Gateway Log into your Government Gateway account and navigate to the Self Assessment section. Your UTR should be displayed once Self Assessment is activated on your account.
What you cannot do: HMRC will not give your UTR to a third party who calls on your behalf without your prior authorisation. You must contact HMRC yourself or through your formally registered agent.
HMRC’s Online Services and Your Government Gateway Account
Your UTR is linked to your Government Gateway account. If you do not already have a Government Gateway account:
- Go to gov.uk/log-in-register-hmrc-online-services
- Select “Create a sign in”
- Provide your email address and create a password
- Verify your identity (using personal details and ideally a passport or driving licence)
- Link your UTR to the account when prompted
Once your Government Gateway account is set up, you can access your Personal Tax Account, file Self Assessment returns, view your tax calculation, make payments, and manage your HMRC correspondence digitally.
Frequently Asked Questions
Do I need a UTR for CIS (Construction Industry Scheme)? Yes. Construction subcontractors must provide their UTR to the contractor before receiving any payments. The contractor uses your UTR to verify your CIS status with HMRC. If you work in construction and do not have a UTR, register immediately – without it, contractors must deduct tax at 30% rather than the standard 20%.
What if my company UTR has not arrived? If more than 21 working days have passed since incorporation without a company UTR, contact HMRC’s Corporation Tax helpline: 0300 200 3410. Bring your Companies House registration number.
Is a UTR the same as a National Insurance number? No. Your NI number (format: AB123456C) is used for employment and benefits records. Your UTR (10 digits) is used for Self Assessment and Corporation Tax. Both exist independently.
Does a UTR expire? No. A UTR is permanent and does not expire. Even if you stop filing Self Assessment for several years, your UTR remains active and can be reused when you re-register.
A Real-Life Example
Client B had been working as a self-employed delivery driver since September 2024. She had heard she needed to register for Self Assessment but kept putting it off, assuming January was the deadline for everything.
When she came to us in November 2025, she had no UTR number and the October registration deadline had already passed. We registered her immediately using form CWF1. Her UTR arrived in the post two weeks later, just in time for us to file her 2024/25 return by the 31 January 2026 deadline, avoiding any penalty.
She also had no idea she could claim mileage at 45p per mile for the first 10,000 business miles. Once we factored that in, her taxable profit and therefore her tax bill came down significantly. Register early and get proper advice from the start. It almost always saves money.
Book your free 15-minute consultation: calendly.com/yourtaxhelp/15min
Need to register for Self Assessment and get a UTR? At Your Tax Help Accountants in Stanmore, we handle the registration process for you – including CWF1 and SA1 forms – and advise on your obligations from day one. Call Talha on 07478 645331, email info@yourtaxhelp.co.uk, or visit yourtaxhelp.co.uk
