What is UTR Number?

Your UTR (Unique Taxpayer Reference) is a 10-digit number that HMRC assigns to you when you register for self-assessment. It is your personal tax identifier and is required whenever you communicate with HMRC about your tax affairs.

You will need your UTR number to:

• File your annual self-assessment tax return
• Communicate with HMRC by phone or in writing
• Set up your Government Gateway account for online filing
• Provide to clients or agencies who request it (e.g., in the construction industry under CIS)

How to get a UTR number:

• Register as self-employed: When you register as a sole trader with HMRC, your UTR is sent by post within 10 working days (or 21 days if you are abroad)
• Register a limited company: When you register with Companies House, HMRC automatically issues a UTR for the company

Your UTR is permanent — it stays with you for life and does not change even if you stop being self-employed and restart later. Keep it somewhere safe and accessible.

Do not confuse your UTR with your National Insurance number. Your NI number is used for National Insurance contributions and benefits, while the UTR is specifically for tax purposes.

If you have lost your UTR, you can find it on previous tax returns, HMRC correspondence, or by calling HMRC's self-assessment helpline.