This is the unique taxpayer reference number issued to anyone in the UK who needs to complete a tax self assessment.
This service is part of the personal tax account, and you can use it to check:
- your tax code
- the information HMRC holds about your employment
- an estimate of how much tax you’ll pay
Find out how to tell HMRC about a change to your personal details.
If HMRC needs to contact you about anything confidential they’ll reply by phone or post.
Contact HMRC:
- for help with questions about Income Tax and Class 4 National Insurance, including issues with:
- your tax code
- tax overpayments or underpayments
- a P800 tax calculation
- to get help with identification and verification problems if you’re trying to register for a personal tax account
- to make a backdated claim for Marriage Allowance if your spouse or civil partner has died
- to apply for Marriage Allowance if you do not have a National Insurance number, because you do not intend to work or study in the UK
Telephone:
0300 200 3300
Outside UK:
+44 135 535 9022
Opening times:
Monday to Friday: 8am to 6pm
Closed on weekends and bank holidays.