Lost my National Insurance number

If you've lost or can't remember your number, you might be able to find it on official paperwork like:

• your P60 (end of year tax statement, given to you by your employer)
• a payslip
• a copy of your annual Self Assessment tax return
• other official correspondence

If you still can't find your number, you can ask HMRC to confirm it by:

• completing and returning form CA5403 - Your National Insurance number
• contacting the National Insurance Registrations Helpline on telephone 0300 200 3502. You will be asked some questions to confirm your identity. If you can answer these questions correctly HMRC will send your National Insurance number by post. If you can not answer the questions you will need to complete form CA5403.

HMRC cannot confirm your National Insurance number by telephone. They will write to you instead.

Date published 29 May 2014

This article is intended to inform rather than advise and is based on legislation and practice at the time. Taxpayer’s circumstances do vary and if you feel that the information provided is beneficial it is important that you contact us before implementation. If you take, or do not take action as a result of reading this article, before receiving our written endorsement, we will accept no responsibility for any financial loss incurred.