A National Insurance number (NINO) is the personal reference HMRC and the Department for Work and Pensions use to record your National Insurance contributions and tax against your name only. It is not a permission to work and it is not an ID card. It is the key that links a lifetime of payslips, employers and benefits to one record, and you keep the same number for life.
What does a NINO look like?
Nine characters: two letters, six digits, then a final letter from A to D, for example QQ123456B. The two opening letters are an administrative prefix, not your initials, and certain combinations are never issued. If a number on a document has the wrong shape, it is not a valid NINO, which is a quick first check when verifying paperwork.
Where does my NINO appear?
On tax-related documents like your payslip, your P60 and letters from HMRC. It is also held in the HMRC app and your personal tax account. Most teenagers are sent their number by letter shortly before they turn 16. If you have lost it, you can recover it online or by post rather than apply for a new one.
Do I need a NINO to start a UK job?
You can start work before your number arrives, but you must show you have the right to work and should apply for a NINO as soon as you can. New UK workers, including arrivals from overseas, apply through gov.uk. Without a number recorded, an employer may run an emergency tax code, so giving it promptly helps your deductions settle correctly.
Why does the same number follow me everywhere?
Because the State Pension is built on a single lifetime record. Every qualifying year of contributions is logged against your NINO, so changing jobs, taking a career break or moving abroad and back does not reset it. A consistent number is how decades of contributions add up to a pension entitlement, which is why HMRC issues one number per person and never reuses it.
Primary sources
- Your National Insurance number — gov.uk — Format, purpose and where the NINO appears
- Apply for a National Insurance number — gov.uk — How adults without a NINO apply, including new UK workers
- Find a lost National Insurance number — gov.uk — Recovering a forgotten NINO online or by post
- Social Security Administration Act 1992 — legislation.gov.uk — Section 2 — the statutory basis for the NI numbering system
Editorial process: how we source and review UK tax content.