Self Assessment UTR Number: How to Get and Use Yours
Your Unique Taxpayer Reference (UTR) is a 10-digit number issued by HMRC when you register for Self Assessment. You need it to file your return, make payments, and manage your tax online.
How to Get Your UTR
When you register as self-employed with HMRC, they issue your UTR by post within 10 working days. It arrives in a letter titled "Welcome to Self Assessment."
Where to Find It
If you have lost your UTR letter:
- Check previous Self Assessment returns or correspondence from HMRC
- Log in to your Government Gateway account — it appears in the Self Assessment section
- Call HMRC's Self Assessment helpline (they can tell you over the phone after identity verification)
What It Is Used For
- Filing your Self Assessment return online
- Making tax payments (used as the payment reference)
- Corresponding with HMRC about your tax affairs
- Your accountant needs it to file on your behalf
- Mortgage applications (lenders may ask for it)
Keep It Safe
Your UTR does not change — it stays the same for as long as you are in Self Assessment. Keep it somewhere secure and accessible.
UTR vs National Insurance Number
Your UTR is for Self Assessment specifically. Your National Insurance number covers all NI contributions and is used across all government services. They are different numbers for different purposes.
Accounted stores your UTR securely and uses it automatically for HMRC submissions.
Accounted handles your bookkeeping, tax estimates, and MTD submissions automatically. Start your free trial — no credit card required.
Tax & Compliance Specialists
Our tax specialists have decades of combined experience in UK sole trader and small business taxation, MTD compliance, and HMRC submissions. All content is reviewed against current HMRC guidance before publication and updated quarterly to reflect legislative changes.
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