If you are self-employed, a company director, a landlord, or have any income that needs to be declared to HMRC outside of PAYE employment, you will need a UTR number. Your Unique Taxpayer Reference is one of the most important pieces of tax identification in the UK yet many people are confused about what it is, how to get one, and where to use it. This complete AccFirm guide answers every question about UTR numbers in the UK for 2026.
What Is a UTR Number?
A UTR (Unique Taxpayer Reference) is a 10-digit number issued by HMRC to identify individuals and businesses for tax purposes. Your UTR is unique to you and remains the same throughout your life you will never be assigned a different one, even if you stop being self-employed and start again years later.
Your UTR is used every time you interact with HMRC’s Self Assessment system. Think of it as your personal tax identification number for self-employment and other income outside PAYE.
Who Needs a UTR Number in the UK?
You need a UTR number if any of the following apply to you:
- You are self-employed as a sole trader or freelancer
- You are a partner in a business partnership
- You are a limited company director receiving a salary and/or dividends
- You earn rental income from a UK property
- You have income from savings, investments, or capital gains that exceed HMRC’s reporting thresholds
- You receive income from abroad
- Your total income from all sources exceeds £100,000 per year
- You have untaxed income from any source over £2,500 per year
- You receive Child Benefit and your household income exceeds £50,000 (High Income Child Benefit Charge)
- You are a trustee of a trust
- HMRC has sent you a notice to file a Self Assessment tax return
What Does a UTR Number Look Like?
A UTR number is exactly 10 digits long. There are no letters. It might be displayed on HMRC correspondence with a space separating the first three and last seven digits, for example: 123 4567890. However, when asked to enter your UTR on forms or systems, you typically enter all 10 digits without spaces.
Do not confuse your UTR with:
- Your National Insurance Number (NI Number): This is formatted as two letters, six digits, and one letter e.g., QQ 12 34 56 A. NI numbers are used across PAYE employment and benefits.
- Your Company Registration Number (CRN): This is the 8-digit reference issued by Companies House to limited companies.
- Your VAT Registration Number: An entirely different reference used for VAT purposes.
How to Get a UTR Number in the UK
Obtaining a UTR number requires registering for Self Assessment with HMRC. The process depends on your situation:
For Self-Employed Individuals (Sole Traders)
You must register for Self Assessment by 5 October following the end of your first tax year of self-employment. For example, if you began trading in July 2025, you must register by 5 October 2026.
The registration process:
- Step 1: Create a Government Gateway account at gov.uk/register-for-self-assessment if you do not already have one
- Step 2: Complete the SA1 or CWF1 (for newly self-employed) form online
- Step 3: HMRC will issue your UTR number by post within 10 working days (up to 21 days for overseas addresses)
- Step 4: Activate your Self Assessment online account using the activation code sent separately by post
For Company Directors
When you register a limited company with Companies House, HMRC is automatically notified and will issue a UTR to the company itself. As a director, you also need a personal UTR for your own Self Assessment tax return. If you do not already have one, register separately via SA1.
For Landlords
If your rental income requires Self Assessment reporting, register using form SA1. If you are already employed and earning rental income, contact HMRC to add property income to your tax affairs they may be able to collect smaller amounts via your PAYE tax code rather than requiring a full Self Assessment return.
Where to Find Your UTR Number
If HMRC has already issued you a UTR, it can be found in the following places:
- HMRC correspondence: Any letter, notice, or tax return from HMRC will display your UTR at the top
- Self Assessment tax return: The SA100 form shows your UTR in the header section
- Your HMRC Personal Tax Account: Log in at gov.uk and navigate to the Self Assessment section
- The HMRC app: Downloadable from the App Store or Google Play your UTR is displayed in your personal details
- Your accountant: If you use a professional accountant, they will hold your UTR on file
If you genuinely cannot locate your UTR, call HMRC’s Self Assessment helpline on 0300 200 3310 (Monday to Friday, 8am to 6pm). You will need to verify your identity before HMRC will confirm your UTR.
What Is a CIS UTR Number?
In the Construction Industry Scheme (CIS), both contractors and subcontractors have their own UTR numbers. If you are a subcontractor working in construction and registered for CIS, your UTR is used to verify your CIS status with contractors before they pay you. The contractor checks your UTR with HMRC to determine whether to deduct 20% (registered subcontractors) or 30% (unregistered) CIS tax from your payments.
CIS UTR numbers are the same format as all other UTRs 10 digits and are obtained through the same Self Assessment registration process. However, CIS registration is separate from basic Self Assessment registration.
Company UTR vs Personal UTR: What Is the Difference?
When you form a limited company, it receives its own 10-digit company UTR (also called a Corporation Tax UTR) separate from any personal UTR the director may have. These are used for different purposes:
| Type | Who It Belongs To | Used For |
| Personal UTR | An individual person | Self Assessment, personal tax returns, CIS |
| Company UTR | A limited company | Corporation Tax returns, company tax affairs |
Directors must maintain both their personal UTR (for their individual Self Assessment return) and their company UTR (for Corporation Tax and company accounts). Using the wrong UTR on an HMRC submission can cause delays and processing errors.
What Happens If You Don’t Register for a UTR When Required?
Failing to register for Self Assessment by the 5 October deadline can result in:
- A £100 late filing penalty from HMRC
- Further penalties of £10 per day after 3 months (up to £900)
- An additional £300 (or 5% of the tax due, whichever is higher) after 6 months and again after 12 months
- Interest charges on any tax paid late
- HMRC investigations into whether you have unreported income
HMRC has significantly increased its use of data analytics to identify self-employed individuals who have not registered. If you receive income from platforms like Uber, Airbnb, Deliveroo, eBay, or Etsy above the £1,000 trading allowance, HMRC is likely aware of it via the Digital Platform Reporting regime that started in 2026.
UTR Numbers for Non-UK Residents
If you are a non-UK resident with UK tax obligations (for example, you have UK rental income or UK employment), you can apply for a UTR by completing form SA1 and posting it to HMRC. The process takes longer than for UK residents typically 21 days. You can also apply through a UK-based accountant or tax agent, such as AccFirm, who can register on your behalf.
Can Someone Else Use Your UTR Number?
No your UTR is personal to you. Sharing it with anyone other than your authorised accountant or tax agent is a significant security risk. Fraudsters sometimes ask for UTR numbers as part of tax refund scams. HMRC will never ask for your UTR via text, email, or social media. If you receive any unsolicited communication asking for your UTR, treat it as a potential scam and report it to HMRC’s phishing team.
Frequently Asked Questions: UTR Number UK
How long does it take to get a UTR number?
HMRC typically issues a UTR number within 10 working days of registration for UK-based applicants, and up to 21 days for overseas applicants. Registering online via gov.uk is the fastest method.
Can I file a tax return without a UTR?
No. You cannot file a Self Assessment tax return without your UTR number. If you have lost yours, contact HMRC on 0300 200 3310 to retrieve it before the filing deadline.
Is a UTR number the same as a tax reference number?
The terms are often used interchangeably, but strictly speaking your UTR is specifically for Self Assessment purposes. HMRC uses various reference numbers your Accounts Office Reference and PAYE Reference are used by employers. Your UTR is the primary reference for personal tax.
Do I need a UTR if I am employed but also have a side hustle?
If your side hustle income exceeds £1,000 per year (the trading allowance), you must register for Self Assessment and obtain a UTR. Income below £1,000 from self-employment is exempt under the trading allowance.