Lost Your National Insurance Number? How to Find It Again

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Lost Your National Insurance Number? How to Find It in 2026

Your National Insurance number is the unique reference that ties your tax and benefits record to you. You keep the same number for life. Losing the physical record of it is common and rarely a problem, because the number itself is never reissued or changed, you simply need to retrieve it.

Here is how to find your National Insurance number in 2026, what counts as official proof, and what to do if nothing turns up.

What your National Insurance number looks like

It follows a fixed format: two letters, six digits, then a final letter, for example, QQ 12 34 56 C. If you have a document showing a number in any other format, it is not a valid National Insurance number.

Where to look first

Before contacting HMRC, check the documents you already have. Your number appears on:

• Your payslips
• Your P60 (the annual summary your employer gives you after the tax year ends)
• Your P45 (issued when you leave a job)
• Letters from HMRC about tax, pensions, or benefits
• Your personal tax account or the HMRC app

If you find it on any of these, you have everything you need, there is no separate "card" to chase. The old plastic National Insurance number cards were phased out years ago and were never required as proof.

The quickest method: the HMRC app or your personal tax account

The fastest way to retrieve your number is online:

1. Sign in to your personal tax account at gov.uk, or open the free HMRC app.
2. Use your Government Gateway user ID and password. If you don't have an account, you can create one, you'll need proof of identity, such as a passport, payslip, or P60.
3. Your National Insurance number is displayed once you're signed in, and you can download a confirmation letter as official proof.

The HMRC app also lets you save your number to a digital wallet, so it's to hand next time.

If you can't get online

If you can't access the app or your online account, you can ask HMRC to post your number to you:

• Complete form CA5403 ("Get your National Insurance number by post") on gov.uk, you fill it in online, then print it and post it to HMRC, or
• Call the National Insurance number helpline.

HMRC will not read your number out over the phone or send it by email or text, for security reasons. It is posted to your registered address and typically arrives within 10 working days (21 working days if you're abroad).

What to do if you've never had a number

If you have never been issued a National Insurance number, for example, you've recently moved to the UK, you cannot "find" one, because there is nothing to retrieve. Instead, you apply for one through the gov.uk application process. You can usually start work before your number arrives, as long as you can prove you have the right to work in the UK; tell your employer the number is on its way.

Keeping your number safe

Once you have it, store it somewhere secure and private. Your National Insurance number is a target for identity fraud, so treat it like any other sensitive credential: share it only with HMRC, your employer, your accountant, your pension provider, or your bank when they have a legitimate reason to ask. HMRC will never ask for it through an unsolicited call, text, or email.

Need a hand?

If you're piecing together your tax records, whether you've lost track of old employments, you're registering for Self Assessment, or you're setting up payroll for the first time, we can help you get everything in order. Get in touch via our contact page and we'll point you in the right direction.

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