Find a lost National Insurance number

Man looking for National Insurance number on computer

If you've lost your National Insurance number, you'll need to find it to make sure your income tax, National Insurance contributions and benefits are dealt with properly. Finding your National Insurance number is usually relatively straightforward. If you have never had one, you'll need to apply for a new National Insurance number.

If you live in the UK, you should automatically get a National Insurance (NI) number just before your 16th birthday. This unique reference number allows HM Revenue & Customs (HMRC) to keep records of your tax and National Insurance contributions. It also ensures that you get the benefits - including the state pension - that you are entitled to

National Insurance contributions are payable for most people who work in the UK. An employer will want to know your NI number before you start a job, so that they can collect the right employee and employer National Insurance contributions, as well as income tax deductions.

How to find your National Insurance number

HM Revenue & Customs no longer issues plastic NI cards. If you have lost or forgotten your NI number, you can find it on your payslip, P60, or on any letters sent to you by HMRC relating to tax, pensions and benefits. You can also view it on your personal tax account if you've registered for one.

If you cannot register for a personal tax account and you still can't find your NI number, you can:

  • fill in and return form CA5403 to HMRC together with 2 identification documents
  • phone the National Insurance numbers helpline on 0300 200 3500

HMRC will not provide your National Insurance number over the phone – it will be posted to you.

How to get a new National Insurance number

If you are between 16 and 19 years old and didn't get an NI number when you turned 16, you can phone the National Insurance numbers helpline on 0300 200 3500.

If you're over 20 and you haven't got a NI number, you need to apply for a National Insurance number. You'll need to provide proof of identity, and it may then take up to 16 weeks to get the new National Insurance number. If you need help, call the National Insurance number application helpline on 0800 141 2079.

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