National Insurance number in the UK: who needs one and how to apply
A National Insurance number (NI number) helps HM Revenue and Customs match your tax and National Insurance contributions to your record. If you have moved to the UK for work, you may need to apply — but first check whether a number has already been assigned to you. An NI number is not proof of immigration status or permission to work.
Check your records before applying
Your NI number stays the same for life, even if you move house, change jobs or update your personal details. Do not apply for a second one. If you have a biometric residence permit, check the back of the card; if you use an eVisa, sign in to your UK Visas and Immigration account. An old payslip, P60 or letter from HMRC may also show the number. Keep it private and share it only when an employer or public service legitimately needs it.
Who can apply and what to prepare
GOV.UK says you can apply if you live in the UK, have the right to work and are working, looking for work or have an offer of employment. You must be in the UK when you apply. Applications are made online through the official government service. Have a passport or eligible national identity card available if you have one. The application may ask for photographs to prove your identity; if you cannot provide them online, you may be asked to attend an appointment or send copies of documents.
After submitting the form, keep the confirmation email and application reference. It can take up to four weeks to receive the number after your identity has been proved. If you have waited longer, moved since applying or your details have changed, contact the application helpline and quote the reference.
You can start work before it arrives
Waiting for the NI number does not by itself prevent you from starting a job. GOV.UK allows you to begin work before it arrives if you can prove your right to work in the UK. The employer checks that right through the appropriate Home Office process; the NI number is a separate tax-record identifier and cannot replace that check. Tell payroll that your application is pending and provide the number when you receive it.
If you already had an NI number but cannot find it, use the official “find your National Insurance number” service rather than applying again. For questions about eligibility to work, check your immigration documents or seek qualified immigration advice; an NI application does not change your visa conditions.
Before you submit
- Look for an existing number on your eVisa, BRP, payslip or P60.
- Confirm you are in the UK and meet the right-to-work requirement.
- Apply only through GOV.UK and save the reference email.
- Do not delay a job solely because the number has not arrived if your right to work is already proven.
Official source: GOV.UK — Apply for a National Insurance number.
