This guide is for internationals who have just moved to the United Kingdom and want to understand how the National Insurance number works. After reading it, you will know who can apply, how to check whether you already have a number, how the application works and what happens once it is submitted.
- What a National Insurance number is
- Checking whether you already have one
- Who can apply
- How the application works
- What happens after you apply
- FAQ
What a National Insurance number is
According to GOV.UK’s guidance on your National Insurance number, the number makes sure your National Insurance contributions and tax are recorded against your name only. It is made up of 2 letters, 6 numbers and a final letter. GOV.UK gives QQ123456B as an example of the format.
The number stays the same for life. Once issued, it appears on tax-related documents such as your payslip and your P60. GOV.UK also has an online service where you can find your number or get a letter that shows it.
To prevent identity fraud, GOV.UK says not to share the number with anyone who does not need it. The organisations that may need it include:
- HM Revenue and Customs (HMRC) and your employer
- the Department for Work and Pensions if you claim state benefits, or the Department for Social Development in Northern Ireland
- your local council if you claim Housing Benefit, or the Northern Ireland Housing Executive
- Electoral Registration Officers, to check your identity when you register to vote
- the Student Loans Company, personal or stakeholder pension providers, ISA providers and authorised investment firms
- websites and apps you sell goods or services through, and cryptoasset services, where they are required to report to HMRC
Checking whether you already have one
Some newcomers already hold a National Insurance number without having applied for one. The GOV.UK page on applying for a National Insurance number says that people with a biometric residence permit (BRP) or an eVisa might have one already. It can be found:
- on the back of the BRP
- by logging into your UK Visas and Immigration (UKVI) account to view your eVisa
Anyone who already has a number does not need to apply for a new one, even if their personal details change. The same number remains in place for life.
Young people who grew up in the UK usually get their number a different way. A UK resident will normally be sent a number in the 3 months before their 16th birthday if they live in the UK and a parent or guardian filled in a Child Benefit claim form for them. Those aged 16 to 19 who did not receive one can check whether they already have a number, or apply online if no Child Benefit claim form was filled in for them.
Who can apply
GOV.UK sets out three conditions. You can apply for a National Insurance number if you:
- live in the UK
- have the right to work in the UK
- are working, looking for work or have an offer to start work
GOV.UK states that BRP and eVisa holders who do not already have a number must apply for one if they plan to work. Applications can only be made from inside the UK, so the process cannot be started before arrival.
In some situations a number is not needed upfront:
- A number is not needed to start an application for benefits or a student loan. If one is needed before the payment can be made, the applicant will be contacted and told how to get one.
- A number is not needed to apply to the EU Settlement Scheme.
These pages do not say which visas or statuses give the right to work. People with a specific immigration question can speak to an adviser regulated by the Office of the Immigration Services Commissioner (OISC) or a solicitor regulated by the Solicitors Regulation Authority (SRA).
How the application works
The application is made through the GOV.UK service linked from the official page. The guide and the service are also available in Welsh (Cymraeg). The official pages used for this guide do not state a fee for applying. They also do not say which questions the form asks or which documents it requests. Those details are shown within the service itself.
Timing matters for new arrivals. GOV.UK says you can start work before you receive your National Insurance number if you can prove you have the right to work in the UK. Waiting for the number does not in itself stop someone from starting a job.
Applicants receive a confirmation email after they apply. The application reference number is at the top of that email.
What happens after you apply
GOV.UK states that it can take up to 4 weeks to get a National Insurance number. You can call the application helpline if:
- you applied more than 4 weeks ago
- you have moved house since you applied
- your personal details have changed since you applied
Callers who have an application reference number are asked to have it ready.
The number then becomes part of starting a job. Getting your National Insurance number is step 1 in GOV.UK’s “Start a new job” steps. To pay you, a new employer will need:
- your National Insurance number
- your bank details
- proof of your identity
- your student loan repayment plan, if you have one
- details of any benefits you get
The employer uses a P45 to work out how much tax to take from your pay. People without a P45 fill in the starter checklist instead.
Your employer must give you a payslip on or before payday. GOV.UK notes that it is your responsibility to make sure you are paying the right amount of tax. If the tax on a payslip looks wrong, the tax code may be incorrect.
FAQ
Can I start working before my National Insurance number arrives?
Yes, if you can prove you have the right to work in the UK. GOV.UK says you can start work before you receive your number on that basis. The number can take up to 4 weeks to arrive. A new employer needs it, along with your bank details and proof of identity, to pay you.
Is there a fee to apply for a National Insurance number?
The official GOV.UK pages used for this guide do not mention any fee for applying. The application is made through the GOV.UK service linked from the official page, which sets out the details of the process.
Do I need a new number if my name or address changes?
No. GOV.UK states that anyone who already has a National Insurance number does not need to apply for a new one, even if their personal details change. The number remains the same for life. If you move house or your details change while your application is still being processed, you can call the application helpline.
Can I apply before I move to the UK?
No. GOV.UK states that people with a BRP or eVisa can only apply when they are in the UK. It also says that BRP and eVisa holders might already have a number. It is shown on the back of the BRP or in the UKVI account for an eVisa.
Official sources: gov.uk · gov.uk
Last verified: 26 September 2026 against the official pages linked above. Rules and fees change; the official page always wins.
This is general information, not legal or immigration advice. Immigration advice in the UK may only be given by advisers regulated by the OISC or by solicitors regulated by the SRA.
Sources
- gov.uk: Apply for a National Insurance number, accessed 26 September 2026 (archived copy)
- gov.uk: National Insurance: introduction, accessed 26 September 2026 (archived copy)
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