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UK Payroll Glossary

NINO(National Insurance number)

A National Insurance number (NINO) is a unique personal reference that HMRC uses to track an individual's National Insurance contributions, Income Tax, and benefit entitlements across their entire working life. The format is two letters, six digits, and a final letter — for example `AB123456C`. Most UK residents are allocated a NINO automatically before their sixteenth birthday; others apply when they arrive to live and work in the UK. Every employer must record a NINO for each employee.

Last updated May 2026

Format and where to find yours

A NINO follows a strict pattern: two letters, six digits, one final letter — for example AB123456C. The letters are always uppercase; certain letter combinations are reserved and will never appear in a real NINO (for example, the letters D, F, I, Q, U, and V are excluded from the first two characters). When written out for humans to read, it is usually spaced as AB 12 34 56 C, although systems store it without spaces.

You can find your NINO in several places:

  • Your payslip. Many UK employers print the NINO on the payslip, near the top alongside your name and employee number.
  • Your [P60](/glossary/p60). The end-of-year summary always shows the NINO used during that tax year.
  • Letters from HMRC. Any formal correspondence — tax codes, statements, coding notices — will show your NINO prominently.
  • Your Personal Tax Account on gov.uk. Sign in and your NINO is on the overview page.
  • Your National Insurance card (if you were issued one before 2011, when HMRC stopped sending them).

Treat your NINO like a password — it is a strong identity signal and should not be shared beyond your employer, HMRC, and benefit agencies.

How NINOs are used

The NINO is the spine that links every piece of your UK tax and benefits record into one coherent account. Specifically:

  • National Insurance contributions — every payment you or your employer makes is filed against your NINO, building up your entitlement to a State Pension and certain benefits.
  • Income Tax through [PAYE](/glossary/paye) — your employer includes your NINO in every FPS submission to HMRC, so the tax paid is attributed to the right person.
  • Benefit claims — Universal Credit, Jobseeker's Allowance, and other DWP benefits all require a NINO to verify identity and contribution history.
  • State Pension entitlement — HMRC counts qualifying years of NI contributions against your NINO to determine what State Pension you will receive.

For employers, recording the correct NINO for every employee is a legal requirement under RTI. If a NINO is wrong or missing, the FPS may still be accepted but HMRC may fail to attribute the contributions correctly — which eventually harms the employee's pension record. Checking the NINO on the P45 or Starter Checklist when a new employee joins is the simplest way to ensure accuracy from day one.

Lost your NINO?

Losing track of your NINO is common and straightforward to fix:

  1. Sign in to your Personal Tax Account at gov.uk — your NINO is on the overview screen.
  2. Request form `CA5403` from HMRC. This is the official form to ask for your NINO in writing; allow several weeks for a reply by post.
  3. Call HMRC's National Insurance helpline on 0300 200 3500. You will be asked security questions to confirm identity before HMRC gives you the number.

If you are a new starter who does not yet have a NINO, you can still begin work immediately. You must apply for one through gov.uk (by booking a "Confirm your identity" appointment at a JobCentre Plus), and once issued, report it to your employer so they can update the payroll record. HMRC requires the NINO to be added as soon as it is available — leaving it missing indefinitely is not permitted under RTI rules.

In Ghugi terms: Ghugi uses an employee's NINO as one of several signals to automatically match payslip PDFs to the right person in a batch — but it is handled with strict privacy controls. The NINO is hashed one-way using HMAC-SHA-256 before any comparison is made; the readable number is never stored anywhere in Ghugi's database. The hash itself is what we store and compare against, keyed by a per-deployment pepper that makes it meaningless outside Ghugi.

Related terms

National InsuranceNational Insurance is a separate UK contribution most workers and employers pay alongside Income Tax.PAYEPAYE is HMRC's system for collecting Income Tax and National Insurance directly from employees' wages before the money reaches…HMRCHMRC stands for His Majesty's Revenue and Customs — the UK government department that collects tax.PayslipA payslip is the document showing what an employee was paid for a specific period — usually a week or a month.

Authoritative source

HMRC: lost National Insurance number →

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Disclaimer: This glossary is for general guidance. Specific UK tax thresholds and statutory rates are checked at publication and re-reviewed every April; always verify against the official gov.uk pages for the current tax year. Ghugi is not a payroll provider and does not give tax or legal advice. For your situation, ask your accountant or HMRC directly.