NIM39205 - National Insurance numbers (NINOs): confirming a NINO: confirmation by individual - form CA5403

Customers can find their National Insurance numbers on payslips, P60s or letters about tax, pensions and benefits. If they have a Personal Tax Account they can also view it there and print a confirmation letter. The quickest way for customers to get their National Insurance number is through logging into or creating a Personal Tax Account or downloading the HMRC app. Their Personal Tax Account allows customers to get confirmation of their National Insurance number, download a letter confirming it, which can be printed off or saved and share their number with employers.

The HMRC app allows customers to view and get confirmation of their National Insurance number and share it with their employers.

If a customer still needs confirmation of their National Insurance number, they should:

• fill in form CA5403 and send it to the address on the form
• phone the National Insurance numbers helpline and answer some questions (they’ll need to fill in form CA5403 if they can’t answer the questions)

HM Revenue and Customs (HMRC) won’t tell customers their National Insurance number over the phone. They’ll post it to the customer and it will arrive within 15 working days.

You can find more information at find a lost National Insurance number.

HMRC action

If the customer phones the NI Registrations Helpline, they will determine the National Insurance number where possible and send confirmation of it to the customer.

If the National Insurance number cannot be found, or the customer cannot be helped on the telephone, they will tell the customer to complete form CA5403.

National Insurance Registration teams will deal with forms CA5403. They will confirm identity and update personal details and, where a National Insurance number can be traced, will send a confirmation of NINO to the customer.

If a customer has never had a NINO, see NIM39325.