How to get a National Insurance number

If you grew up in the UK and a parent claimed Child Benefit for you, a number was issued automatically shortly before your sixteenth birthday and posted to you. Many people have one without remembering it.

Look for it on: a payslip, a P60 or P45, a letter from HMRC or the Department for Work and Pensions, a pension statement, or in the HMRC app and your personal tax account. If none of those work, you can ask HMRC to confirm it — they will post it to your registered address rather than give it over the phone.

You never need to apply for a second one. Applying twice creates duplicate records that take longer to untangle than finding the original.

You need the right to work or study in the UK. That means British or Irish citizenship, settled or pre-settled status, a visa permitting work or study, or another form of leave with the right conditions.

You must be in the UK when you apply. Applications cannot be made from abroad.

If your visa gives you the right to work, you may already have a number printed on your biometric residence permit if you were issued one — check before applying. Since the move to eVisas, newer arrivals generally will not have this and will need to apply.

You do not need a National Insurance number to start work, to open a bank account, or to rent. Employers, banks and landlords sometimes ask for one anyway, and it is worth knowing that an employer requiring one before your first day is applying a rule that does not exist.

Start at the official GOV.UK application page. The service asks for your personal details, your address history, and details of your immigration status if relevant.

You then need to prove your identity. Most applicants can do this through the online service using a passport or biometric residence permit, photographing the document and taking a short video or photo of themselves. If the automated check cannot verify you, HMRC will contact you and may ask you to post documents or attend an appointment.

You will get a reference number when you submit. Keep it — it is what you quote if you need to chase.

The stated timescale is usually up to eight weeks from a completed application, though many are considerably faster. Chasing before eight weeks generally achieves nothing.

This is where money is actually lost. Without a National Insurance number and a P45 from a previous UK job, your employer will normally put you on an emergency tax code, which taxes you as if you had no personal allowance or a reduced one. You can overpay significantly across several months.

The fix is to give your employer the information they need on day one. If you have a P45 from a previous UK employer, hand it over. If not, complete the HMRC starter checklist — a short form that tells the employer which statement applies to you so they can operate the right code. Getting this right at the start avoids most emergency tax situations even without a National Insurance number.

Once you have the number, give it to your employer immediately and check your tax code in your personal tax account or the HMRC app. If you have overpaid, HMRC usually corrects it automatically once records match, and refunds through payroll or after the tax year ends.

Keep the number safe. It is a permanent identifier and a target for identity fraud. Give it only to employers, HMRC, the Department for Work and Pensions, your pension provider, your accountant and your local council for council tax and benefits purposes. Nobody else has a legitimate reason to demand it, and no recruiter needs it before making an offer.