Your National Insurance Number

What Is a National Insurance Number?

Your National Insurance number (often abbreviated to NI number or NINO) is a unique reference number used by HMRC and the Department for Work and Pensions (DWP) to track your National Insurance contributions and tax records.^[1]

It is not a form of identification. It does not prove your identity, your right to work in the UK, or your immigration status. It is simply a reference number that ensures your contributions and tax are correctly recorded against your name.

The NI Number Format

A National Insurance number consists of:^[1]

• Two prefix letters (e.g. QQ, AB, NM)
• Six digits arranged in three pairs (e.g. 12 34 56)
• One suffix letter (A, B, C, or D)

The full format looks like: QQ 12 34 56 A

How You Get a National Insurance Number

Most people born in the UK receive their NI number automatically. HMRC sends it in a letter shortly before a young person’s 16th birthday, provided they were registered for Child Benefit.^[1]

If you were not registered for Child Benefit, or you have moved to the UK from abroad, you will need to apply for one.

Applying for an NI Number

If you do not have a National Insurance number and need one, the process is:^[2]

1. Call the application line on 0800 141 2075 (or textphone 0800 141 2438)
2. You will be asked basic questions about your identity and circumstances
3. You may receive your NI number by post, or you may be asked to attend an Evidence of Identity interview at a Jobcentre Plus office
4. Bring original identity documents (passport, biometric residence permit, national identity card) to the interview

How to Find Your National Insurance Number

If you already have an NI number but cannot remember it, you can find it in several places:^[3]

• Payslip — your NI number is usually printed on every payslip
• P60 — end-of-year certificate from your employer
• P45 — given when you leave a job
• Tax letters from HMRC — coding notices, Self Assessment statements
• Benefit letters from DWP
• HMRC personal tax account — log in at gov.uk/personal-tax-account
• HMRC app — available on iOS and Android

If you still cannot find it, call the National Insurance helpline on 0300 200 3500.

Keeping Your NI Number Safe

Your NI number does not change throughout your life, so it is important to keep it safe. While it is not a high-risk piece of data on its own (unlike, say, a bank account number), you should:

• Never share it with anyone who does not need it
• Be cautious if anyone asks for it by email or text — HMRC will never ask for your full NI number by email
• Store the original letter in a safe place

Your NI Number and Employers

When you start a new job, your employer will ask for your NI number to set up your PAYE record. They use it to:

• Report your earnings and tax to HMRC through Real Time Information (RTI)
• Ensure your NI contributions are recorded against your record
• Collect the correct amount of Income Tax using your tax code

If you do not know your NI number when you start work, your employer should still put you on the payroll. They can use a temporary reference until you provide the real one.

Common Situations

Changed your name?

If you change your name (for example, after marriage), tell HMRC so they can update your records. Your NI number itself does not change — only the name associated with it.

Lost your NI letter?

HMRC does not reissue the original NI letter, but you can find your number through the methods listed above. You can also request written confirmation by calling the helpline.

Two NI numbers?

Occasionally, administrative errors result in a person being issued two NI numbers. If this happens, contact HMRC immediately so they can merge your records. Having two numbers can cause problems with your NI record and benefit entitlements.

Further Reading

• What Is National Insurance? — how NI works and what it funds
• NI and the State Pension — how your NI record builds pension entitlement
• NI Credits — free credits that count towards your NI record