What is UTR Number? UK Definition 2026/27
Quick Answer
Unique Taxpayer Reference - your 10-digit identifier for Self Assessment with HMRC.
Definition of UTR Number
A UTR (Unique Taxpayer Reference) is a 10-digit number assigned when you register for Self Assessment. It's your identifier for all Self Assessment correspondence with HMRC.
Your UTR is different from your National Insurance number and doesn't change even if you stop self-employment and restart later. Keep it safe but don't share it unnecessarily.
UTR Number — Key Facts for 2026/27
| Format | 10 digits (e.g., 1234567890) |
| Issued when | Registering for Self Assessment |
| Used for | Self Assessment, CIS, partnerships |
| Time to receive | Up to 10 working days |
How UTR Number Works — Example
- 1Register for Self Assessment online
- 2UTR sent by post within 10 days
- 3Also found on:
- 4- Previous tax returns
- 5- Self Assessment statements
- 6- HMRC correspondence
- 7- Personal Tax Account online
How UTR Number Affects Your Tax
You need your UTR to file Self Assessment, register for CIS, and set up a limited company. Keep it confidential but accessible for tax matters.
Official HMRC Guidance on UTR Number
For official guidance, refer to HMRC's documentation. Tax rules can change, so always verify current rates and thresholds on gov.uk.
HMRC: Register for Self AssessmentFrequently Asked Questions about UTR Number
Accuracy Note
This information is for guidance only and is based on 2026/27 tax year rates. Tax rules are complex and your circumstances may differ. For personal advice, consult a qualified accountant or tax adviser.