In 2026 your National Insurance number is usually on a payslip, P60 or letter about tax, pensions or benefits. Otherwise the HMRC app and your personal tax account show it. HMRC won't say it by phone, but can post it.
The HMRC app and your personal tax account also let you download a letter showing your number.
As a self-employed tradesperson you need it to register as a sole trader, and a contractor needs it to verify you under the Construction Industry Scheme (CIS). The points below follow GOV.UK as checked on 19 October 2026.
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Where to look first
GOV.UK says you will usually already have a National Insurance number if you have lived or worked in the UK, even if you do not know it. If you grew up in the UK, you were normally sent a letter with it shortly before your 16th birthday, as long as a parent or guardian claimed Child Benefit for you. Check:
- A payslip or P60 from any job you have had, including one from years ago.
- Letters about tax, pensions or benefits, such as a tax code letter or a State Pension statement.
- The HMRC app, if you live in the UK.
- Your personal tax account on GOV.UK, if you already have one.
- Apple or Google Wallet, if you saved it there before.
GOV.UK also has a short "Check how to find your National Insurance number" tool that asks about your situation and tells you the best place to look. If you can't use the app or an online account, you can ask HMRC to post it to you: fill in GOV.UK's form online, print and sign it, and send it with documents that confirm your identity.
What it looks like
A National Insurance number is 2 letters, 6 numbers and a final letter, for example QQ123456B. It stays the same for life. Do not mix it up with your UTR (Unique Taxpayer Reference), the 10-digit number HMRC sends when you register for Self Assessment, or with a CIS reference.
| National Insurance number | UTR | |
|---|---|---|
| Looks like | 2 letters, 6 numbers, 1 letter (QQ123456B) | 10 digits |
| When you get it | Usually shortly before your 16th birthday | After you register for Self Assessment |
| Where to find it | Payslip, P60, HMRC letters, HMRC app, personal tax account | Self Assessment letters and returns, HMRC app, personal tax account |
Our guide on what a UTR number is and where to find it covers the other number.
If you have never had one
If you moved to the UK from abroad, you may already have one if you have worked or claimed benefits here, or it may be on the back of a biometric residence permit or in your UK Visas and Immigration account. If you have never had one, you apply online, and you must have the right to work in the UK. If you are 16 to 19 and never got one, GOV.UK says to apply online too. GOV.UK says it can take up to 4 weeks after you have proved your identity, and you can start work before it arrives if you can prove your right to work.
Why a tradesperson needs it
- Registering as a sole trader. You give your National Insurance number when you register with HMRC for Self Assessment as a sole trader. Our guide on registering as a sole trader has the steps.
- CIS. To verify a sole trader subcontractor, the contractor needs your UTR and your National Insurance number, and they must match the details you registered with exactly. A temporary number, starting with "TN" or with 2 digits, can't be used to verify you. If the contractor cannot verify you, deductions can be 30% instead of 20%.
- Your National Insurance record. Your number is how your National Insurance contributions and tax are recorded against your name. Class 2 contributions (paid, or treated as paid once profits reach £7,105 in 2026-27) count towards your State Pension; Class 4 contributions do not. You can check your National Insurance record online to see any gaps.
- Platforms that report to HMRC. Websites and apps you sell services through may ask for it if they are required to report your earnings to HMRC.
Keep it safe
GOV.UK says not to share your National Insurance number with anyone who does not need it, to prevent identity fraud. HMRC, an employer, a contractor verifying you under CIS, your pension provider and some platforms that report to HMRC may need it. A householder paying you for a job does not.
What this means for you
Look on an old payslip or P60 first, then the HMRC app or your personal tax account. Write the number down with your UTR somewhere safe, because you will need both to register, to get paid properly by contractors under CIS, and when anyone files your tax for you.
This is general information to help you understand the rules. It isn't tailored to your circumstances, so check your own position before acting on it.
Steps to find it
- Check a payslip, P60 or any letter from HMRC, DWP or a pension provider.
- If you have none, sign in to the HMRC app or your personal tax account and download a letter showing your number.
- Still stuck? Use GOV.UK's "Check how to find your National Insurance number" tool.
- If you have never had one, apply online and prove your identity.
- Keep it with your UTR, and give a contractor your UTR, National Insurance number and the exact legal or trading name you registered with.
Use the free MTD check to see when Making Tax Digital starts for you, and the trades section for more guides on tax for trades.
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Questions people ask
Can HMRC tell me my National Insurance number over the phone?
No. GOV.UK says HMRC cannot give you your National Insurance number over the phone or on webchat. Use the HMRC app or your personal tax account, where you can download a letter showing it, or ask HMRC to post it to you using GOV.UK's print-and-post form.
What does a National Insurance number look like?
It is 2 letters, 6 numbers and a final letter, for example QQ123456B. It is a different number from your UTR, which is the 10-digit reference HMRC gives you for Self Assessment.
Does my National Insurance number change if I go self-employed?
No. GOV.UK says your National Insurance number stays the same for life, even if your personal details change. You use the same number as an employee and as a sole trader.
Do I need a new National Insurance number if I change my name?
No. If you already have a National Insurance number you do not need to apply for a new one, even if your name or other personal details change. Tell HMRC about the change instead.
How long does it take to get a National Insurance number?
If you have never had one, you apply online. GOV.UK says it can take up to 4 weeks to get your number after you have proved your identity. You can start work before it arrives if you can prove your right to work in the UK.
Sources
- Find your National Insurance number (GOV.UK)
- National Insurance: Your National Insurance number (GOV.UK)
- Apply for a National Insurance number (GOV.UK)
- Check your National Insurance record (GOV.UK)
- What you must do as a Construction Industry Scheme (CIS) contractor: Verify subcontractors (GOV.UK)
- What you must do as a Construction Industry Scheme (CIS) subcontractor: Get paid (GOV.UK)
- Get your National Insurance number by post (GOV.UK)
- Set up as a sole trader: Register as a sole trader (GOV.UK)
This is general information to help you understand the rules. It isn't tailored to your circumstances, so check your own position before acting on it.
Righto Tax is a trading name of NJG Consultancy Ltd, registered in England and Wales, company number 16095900. Registered office: Jubilee House, East Beach, Lytham St Annes, FY8 5FT.
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