NI number UK: how do I find my NI number in the UK?

If you’re wondering, “How do I find my NI number in the UK?” or “How do I get my UK National Insurance number?”, you’re not the only one. Your National Insurance number stays with you for life in the UK, so it’s worth knowing exactly where to look when you need it.

To keep it simple, there are 3 straightforward ways to find it:

• Check documents you already have – payslips, P45s or P60s from your employer, and any letters about tax, benefits or student loans from HMRC or the Department for Work and Pensions (DWP).
• Look in your online accounts – you can usually see your NI number in your personal tax account or your employer’s online payroll portal once you’ve signed in.
• Ask for it securely – if you still can’t find it, you can request it from HMRC using their official online and postal services.

Next, we’ll walk through which documents and online accounts to check first, so you can get your NI number quickly and safely.

Table of contents

• Where to find your NI number on official documents and letters
• How to get your NI number in the UK if you’ve never had one
• How to apply for a National Insurance number online or by phone
• Common mistakes to avoid when searching for or applying for a UK NI number
• How to find or apply for your National Insurance number in the UK
• What to do if you still cannot find your NI number and when to contact HMRC
• How to recover or find a lost National Insurance number in the UK

Where to find your NI number on official documents and letters

If you’re wondering how to find your National Insurance (NI) number in the UK, the best place to start is with paperwork you already have at home.

Your NI number usually appears on:

• Payslips and P45/P60 forms – look near the top where your personal details are shown.
• Letters about tax or benefits – for example, letters from HMRC or the Department for Work and Pensions about Income Tax, Universal Credit or State Pension.
• Student loan letters – if you studied in the UK, your NI number may be on letters from the Student Loans Company.
• Personal tax account printouts – if you’ve printed anything from your HMRC online account, your NI number is often on there.

Keep these documents safe – they can help you confirm your NI number quickly whenever you need it.

How to get your NI number in the UK if you’ve never had one

If you’ve checked all your usual letters, payslips and online accounts and you’re sure you’ve never had a National Insurance (NI) number, you’ll need to apply for one. This is different from searches like “how do I find my NI number in the UK” or “how to get my NI number in UK” where you’re trying to track down an existing number – here, you’re starting from scratch.

First, check you’re eligible:

• You usually need to be aged 16 or over.
• You must be living in the UK and have the right to work or study here.

Then, get your documents ready:

• Your passport or national ID card.
• Your Biometric Residence Permit (if you have one).
• Proof of your UK address, such as a tenancy agreement, council tax bill or bank statement.

When you’re ready, apply through the official National Insurance number application service on the UK government website or by phone. In the next section, we’ll walk through those steps in detail so you know exactly what to expect.

How to apply for a National Insurance number online or by phone

If you’re still searching things like “NI number UK”, “how do I find my NI number in the UK?” or “how to apply for a UK NI number”, it’s time to go straight to the official services run by the Department for Work and Pensions.

Apply online

Most people now start their National Insurance number application online. You’ll usually:

• fill in a short online form with your personal details and UK address
• upload proof of identity (for example, your passport, biometric residence permit (BRP) or national identity card)
• get a confirmation message and reference number once you’ve sent your application

You can start on the official government website at gov.uk/apply-national-insurance-number.

Apply by phone

If you can’t use the online service or you need extra support, you can call the National Insurance number application helpline. The adviser may:

• ask you some security questions to confirm who you are
• post you a paper application form if they can’t complete it with you over the phone
• explain which original documents you’ll need to send and where to post them

Keep any reference numbers and letters you receive somewhere safe – you may need them later if you change job, contact HMRC or need to track your application.

Common mistakes to avoid when searching for or applying for a UK NI number

When you’re tired, stressed and searching things like “ni number uk”, “how do I find my ni number in the uk” or “how to apply for a uk ni number”, it’s easy to click the wrong link or share the wrong info. Here are the main mistakes to avoid.

• Using an old address – HMRC letters go to the address they already have for you. If you’ve moved around, especially between shared houses, update your current address with them before you apply.
• Guessing or re-using someone else’s number – never copy a partner’s or friend’s NI number, even “just for now”. It can cause serious issues with your tax record, pension and any future benefits.
• Paying unofficial “agents” – applying is free. Avoid anyone on social media, WhatsApp, Telegram or similar who offers to “get you a number faster” for a fee.
• Sending photos on unsafe channels – only upload your passport, BRP or other ID through official UK government services, not to random email addresses or via messaging apps.

How to find or apply for your National Insurance number in the UK

Your National Insurance (NI) number is important for work, tax and accessing certain benefits in the UK. If you’ve already been issued one, there are a few quick ways to find it.

• Use your personal tax account or the HMRC app – log in to your personal tax account or the HMRC app to see your NI number. As set out in the official government guidance, you can download a letter that shows your National Insurance number.
• Check your official documents – your NI number usually appears on payslips, P60s, letters about tax or benefits and, in some cases, on your student loan statements.

If you cannot prove your identity online, live abroad or have never had an NI number, you may need to apply instead of just looking it up.

• If you cannot verify your identity online – the government may ask for extra documents or invite you to an interview. Once they have everything they need, they’ll send your NI number in a confirmation letter.
• If you live abroad – you may still be able to apply, depending on your circumstances. Check the latest rules on the official NI number page before you start a job that’s linked to the UK.
• If you’ve never had an NI number – you usually apply online first. After that, allow time for checks and for your confirmation letter to arrive. Employers in the UK normally let you start work while you’re waiting, as long as you can show you have the right to work here.

For full, up-to-date guidance, always refer to the official government page on how to find or get your National Insurance number: gov.uk/find-national-insurance-number.

What to do if you still cannot find your NI number and when to contact HMRC

If you’ve tried all the options we’ve already covered and you’re still wondering how to find or apply for your National Insurance (NI) number in the UK, it’s time to contact HMRC directly.

Before you contact HMRC, make sure you have:

• your full name, date of birth and current UK address
• any previous UK addresses you’ve lived at
• your passport or biometric residence permit details (if you have them)
• your payslip or P45/P60 if you’re working in the UK

You should contact HMRC if:

• you need your NI number urgently for a new job, benefits claim or student finance application
• you think someone else is using your NI number
• you applied for an NI number several months ago and haven’t had an update

HMRC can confirm your existing NI number or tell you what to do next – though they won’t issue a new one if you already have one.

How to recover or find a lost National Insurance number in the UK

You only ever get one National Insurance (NI) number in your lifetime – HM Revenue & Customs (HMRC) will not issue a new one if you lose it. The good news is that you can usually find it quickly using free, official services.

Start by checking your:

• Personal tax account on GOV.UK
• HMRC app on your phone or tablet
• Payslips, P45 or P60 from your employer
• Letters about tax, pensions or benefits from HMRC or the Department for Work and Pensions

If you still cannot find your NI number, you can ask HMRC to confirm it by post. This is free, but it can take a little time, so try the quicker options above first.

Be careful of websites or companies that say they can get your NI number for a fee. As the TUC guidance explains, your National Insurance number is always issued free by HMRC, and you never need to pay a third party to “recover” it.

Keep your NI number safe and use only official channels. This helps protect your tax record, your benefits and your future entitlement to things like the State Pension.