A National Insurance number is your personal reference for the UK tax and benefits system. It is free, it stays the same for life, and you need one to work, though you are allowed to start a job before it arrives. This guide explains who needs one, how to apply, how long it takes, and what to do if you might already have one.
What a National Insurance number is
Your National Insurance (NI) number makes sure the National Insurance contributions and tax you pay are recorded against your name. It looks like two letters, six numbers and a final letter, for example QQ 12 34 56 C. You keep the same number for life, even if you change jobs, leave the UK, or change your name.
Do you need one, and can you work without it?
You need an NI number if you work in the UK. You can, however, start work before your number is issued, as long as you can prove you have the right to work. Give the number to your employer as soon as you receive it so your contributions are recorded correctly. You do not need an NI number to open a bank account, rent a home, or apply for a student loan.
Is it free?
Yes. Applying for a National Insurance number is completely free through the official GOV.UK service. Anyone charging you a fee to get one is a third party you do not need. Always apply through gov.uk/apply-national-insurance-number.
Check whether you already have one
Some newcomers are issued a number automatically. Before applying, look for it in these places:
- On your biometric residence permit (BRP), if you have one.
- In your UKVI account or eVisa record.
- On any previous UK payslip, P60, or letter from HMRC.
If you already have a number, you do not need to apply again. If you cannot find it but believe you have one, you can ask HMRC to confirm it rather than applying for a new one.
How to apply
- Make sure you are in the UK. You can only apply once you have arrived.
- Go to the official apply for a National Insurance number service on GOV.UK.
- Confirm your right to work or right to live in the UK, and provide your identity details. You may be asked to upload photos of an identity document such as your passport or residence permit.
- Submit the application and keep your reference. If your identity cannot be verified digitally, you may be asked to send documents or attend an appointment.
- Wait for your number to arrive by letter.
How long it takes
It can take up to four weeks to receive your National Insurance number after you apply. If more than four weeks have passed, you can contact the National Insurance number application helpline to chase it. Because you can work in the meantime, a delay does not need to stop you starting a job.
What you use it for
- Paying the correct Income Tax and National Insurance on your wages.
- Building entitlement to benefits and the State Pension.
- Registering with HMRC if you become self-employed.
- Applying for certain benefits and services that ask for it.
Frequently asked questions
Can I apply for a National Insurance number before I arrive in the UK?
No. You can only apply once you are physically in the UK. Wait until you have arrived, then use the GOV.UK service.
What if I start a job before my number comes through?
That is allowed. Tell your employer you have applied, prove your right to work, and hand over the number as soon as it arrives so your records are corrected.
Does my National Insurance number ever change?
No. It is yours for life and does not change if you switch jobs, move away, or change your name.
I lost my National Insurance number. Do I reapply?
No. Check a payslip, P60, or HMRC letter first, or ask HMRC to confirm your existing number. Applying again is not the right route if you already have one.
Once you are working, check your tax is correct: see our guide to UK tax codes for newcomers, and the wider UK money guide for newcomers.
