Where to Find Your UK Tax Identification Number

The UK tax identification number isn’t a single document you can pull out of a drawer. His Majesty’s Revenue and Customs (HMRC) issues different reference numbers for different purposes, and the one you need depends on who’s asking. For most individuals, the number that functions as a UK TIN is your National Insurance (NI) number. If you file a Self Assessment return or run a limited company, you’ll also have a Unique Taxpayer Reference (UTR). Businesses have VAT and PAYE references on top of that.

Which Number Counts as Your UK TIN

A foreign bank, broker, or employer asking for a “Tax Identification Number” is the reason most people go looking. The UK doesn’t print those exact words on any document, but the OECD recognises two UK numbers as TIN equivalents: your NI number and your UTR.

For most UK residents, the correct answer is your National Insurance number. HMRC’s own Common Reporting Standard guidance confirms this.¹ If you’re self-employed or the account relates to business income, a foreign institution may specifically want your UTR instead.²

A NI number has the format of two letters, six digits, and a final letter, for example QQ 12 34 56 B. A UTR is a 10-digit number for individuals, or 13 digits in some business contexts, and may appear on paperwork labelled only “tax reference.”³⁴

Where to Find Your National Insurance Number

Look at paperwork you already have. Your NI number appears on payslips, on your P60 (the annual statement your employer sends after each tax year), and on any HMRC or Department for Work and Pensions letters about benefits, pensions, or tax.³

If none of that is to hand, sign into your Personal Tax Account or open the HMRC app. Both show the number once you’ve verified your identity, usually with a passport or driving licence.⁵ The dedicated “Find your National Insurance number” service on GOV.UK displays it immediately after identity checks.⁶

Where to Find Your Unique Taxpayer Reference

Your individual UTR is printed on previous Self Assessment tax returns, on notices to file a return, and on HMRC payment reminders. Some documents label it “reference,” “UTR,” or “official use” rather than spelling it out.⁷ It also sits inside your Personal Tax Account and the HMRC app.⁴

A limited company’s UTR appears on Corporation Tax letters from HMRC, including the CT603 notice to deliver a company tax return. Never received one, or lost track of it? You can request the Corporation Tax UTR online, and HMRC posts it to the address registered with Companies House.⁴

Partnership UTRs work the same way. Check your Business Tax Account, the HMRC app, or any partnership tax returns and HMRC correspondence.⁷

Where to Find VAT and PAYE References

Your VAT Registration Number sits on the VAT registration certificate HMRC issued when you first registered, and inside your VAT online account.⁸ To verify another business’s VAT number, HMRC runs a free “Check a UK VAT number” service online.

Employers can find their PAYE Reference on HMRC PAYE letters, on employees’ P45 and P60 forms, and inside their payroll software. The reference is a three-digit tax office number followed by a forward slash and a unique employer code, such as 123/AB456.⁹

If You’ve Never Had One

Applying for a National Insurance Number

Moved to the UK and never had a NI number? Apply online through GOV.UK. You’ll need a passport from any country, or a national identity card from an EU country, Norway, Liechtenstein, or Switzerland. The application may ask you to upload a photo of yourself holding your passport along with other identity documents.¹⁰

Without those documents you can still apply, but expect to attend an in-person appointment to prove who you are. Once your identity is confirmed, the number arrives within about four weeks.¹⁰

Registering for Self Assessment to Get a UTR

You get a UTR by registering for Self Assessment. The deadline is 5 October following the end of the tax year in which you first need to file. So if you became self-employed during the 2024–25 tax year, you needed to register by 5 October 2025.¹¹

After online registration, HMRC posts your UTR within about 15 days. Longer if you live outside the UK. If you registered and are still waiting past that window, GOV.UK shows current reply times.⁴¹²

If Yours Is Lost

For a lost UTR, try your Personal Tax Account or the HMRC app first; both display it instantly once you sign in. Failing that, call the Self Assessment helpline on 0300 200 3600. After identity checks, HMRC posts the number to you, typically within about 15 days.⁴

For a lost NI number, the online “Find your National Insurance number” service is fastest.⁶ If that doesn’t work, you have two options: ask HMRC to send a confirmation letter (up to 10 working days in the UK, 21 abroad), or complete form CA5403 online, print and sign it, and post it in with identity documents.¹³

For a VAT number, sign into your VAT online account; HMRC’s digital assistant handles general VAT queries. The phone helpline exists too, but its security checks often require the number you’re trying to find, so online is usually the practical route.⁸ For a lost PAYE Reference, check HMRC correspondence about your PAYE scheme, employees’ P45 or P60 forms, or your payroll software, then fall back to HMRC’s employer helpline if needed.

Keeping Your Tax Numbers Safe

Your NI number and UTR are the keys to your tax identity. Anyone who gets both can attempt fraudulent returns or try to access your HMRC account. HMRC’s guidance is to share your NI number only with people or organisations that genuinely need it.¹⁴

If something in your HMRC online account looks wrong, change your password straight away and report the suspicious activity through the security console in HMRC online services. You’ll need your NI number, an email address, a phone number, and a description of what you’ve spotted.¹⁴

1
GOV.UK. HMRC Internal Manual – IEIM402040 – Reportable Information: Tax Identification Number CRS
2
GOV.UK. HMRC Internal Manual – IEIM902330 – Tax Identification Number (TIN)
3
GOV.UK. National Insurance: Introduction – Your National Insurance Number
4
GOV.UK. Find Your UTR Number
5
GOV.UK. Personal Tax Account: Sign In or Set Up
6
GOV.UK. Find Your National Insurance Number
7
HM Revenue & Customs. Unique Taxpayer Reference – HMRC Patterns for Services
8
GOV.UK. VAT: General Enquiries
9
HM Revenue & Customs. Employer PAYE Reference – HMRC Patterns for Services
10
GOV.UK. Apply for a National Insurance Number – How to Apply
11
GOV.UK. Self Assessment Tax Returns: Penalties
12
GOV.UK. Check How to Register for Self Assessment
13
GOV.UK. Get Your National Insurance Number by Post
14
GOV.UK. Report Suspicious Activity Happening in Your HMRC Online Account