Form

Get your National Insurance number

Use your personal tax account to view your National Insurance number or download a letter confirming it, or use form CA5403 to get your number by post.

Documents

View your National Insurance number (sign in using Government Gateway)

Apply by post (using form CA5403)

CA5403 part 2: your documents

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Details

If you already have a National Insurance number

If you’ve forgotten your National Insurance number or need a letter confirming it, you can use your personal tax account to view or download, print, save or share a letter with it on.

If you do not have a personal tax account, you can register for one now.

If you’re unable to register for a personal tax account

Fill in part 1 of form CA5403 on-screen, then print and post it to HMRC.

If you cannot provide all the information asked for in part 1 you may have to fill in part 2 as well. Part 1 will tell you if you need to print, then fill in part 2. If you need to fill in parts 1 and 2 of CA5403 send them to HMRC together.

It can take up to 15 days to get your National Insurance number by post.

Send the print and post form to:

National Insurance contributions and Employers Office
HM Revenue and Customs
BX9 1AN

Before you start using the CA5403 postal form

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You’ll need to fill in the CA5403 fully before you can print it. You cannot save a partly completed form so gather all your information together before you start to fill it in.

If you do not have a National Insurance number

You can apply for a National Insurance number if you’ve never had one.

Published 9 April 2014
Last updated 7 November 2018 + show all updates
  1. Guidance updated as you can now use your personal tax account to view or download, print, save or share a letter with your National Insurance number on.
  2. Updated form CA5403 to provide HMRC with enough information to confirm a NINO.
  3. An online service is now available.
  4. Amended postal address to: National Insurance Contributions and Employer Office, HM Revenue and Customs, BX9 1AN.
  5. Added translation