What Is a Tax Identification Number (TIN) | Companies MadeSimple

You might see the phrase “Tax Identification Number” on an international form, a banking application, or when setting up a business. It can feel confusing because in some countries, people and businesses are identified for tax using one main number.

In the UK, it works differently.

The UK doesn’t issue one single “TIN” for each individual or business. Instead, the UK uses a few different identifiers, and the right one depends on who you are (individual or business) and what you’re doing (employment, Self Assessment, VAT, payroll, company registration, and so on). 

This guide explains what a UK “TIN” usually means in practice, which numbers count as UK “TIN equivalents”, when you might be asked for one, and how to find the right number fast.

Key takeaways

• The UK does not have one single, universal “Tax Identification Number (TIN)”. Instead, different numbers act as the “TIN equivalent” depending on whether you are an individual or a business.
• If you are self-employed or you run a company, the number most commonly used as a tax identifier is your Unique Taxpayer Reference (UTR).
• If you are an employee, the number most often used to identify you for UK tax and work purposes is your National Insurance number (NINO).
• Limited companies also have a Company Registration Number (CRN) from Companies House, which identifies the company legally (not for paying tax).
• If your business registers for VAT, HMRC issues a 9-digit VAT registration number and confirms it by post.

1. Does the UK have a Tax Identification Number (TIN)?

A Tax Identification Number (TIN) is a general term used internationally for a number (sometimes letters and numbers) that identifies a taxpayer for tax purposes. 

The important bit is this:

The UK does not operate a single, universal TIN system. Instead, the UK uses multiple identifiers that can serve as a “TIN equivalent” depending on the situation. 

So if a form asks for a “UK TIN”, it usually means:

“Which UK tax or registration number identifies you (or your business) in this context?”

2. UK Tax ID equivalents explained

Below are the most common UK identifiers that organisations treat as “TIN equivalents”.

Unique Taxpayer Reference (UTR)

What it is: 

A UTR is a unique reference used by HMRC to identify a taxpayer (this can be an individual, a company, or a partnership, depending on the type of UTR).

Who gets one:

• Individuals who register for Self Assessment
• Many businesses and organisations that need to be identified by HMRC for tax matters 

When you’ll use it:

• Self Assessment
• Corporation Tax (for limited companies)
• Some business and compliance processes where HMRC identification is required

Where to find it:

You can find a UTR on previous tax returns and other HMRC documents (like notices to file or payment reminders), and in your relevant HMRC online account/app in many cases. 

National Insurance number (NINO)

What it is: 

Your National Insurance number is used to record National Insurance contributions and is commonly used as an identifier for individuals in work and personal tax contexts.

Who gets one:

• Individuals (not companies)

When you’ll use it:

• Employment and payroll processes
• Personal tax-related admin
• Some forms that ask for a UK tax identifier for an individual

Where to find it:

You can find your NINO on documents you already have (for example a P60 or payslip), and in your personal tax account or HMRC app if you use those services. 

Company Registration Number (CRN)

What it is:

A CRN is the company’s unique registration number issued when a company is incorporated at Companies House.

Who gets one:

• Limited companies and LLPs registered with Companies House

When you’ll use it:

• Company identification (for example, when proving the company exists, opening accounts, and many legal or admin checks)
• Often requested alongside tax numbers, but it is not the same as a HMRC tax reference

Where to find it:

You can find your CRN on your company's certificate of incorporation/other official documents, the official Companies House register, or in correspondence from your accountant or formation agent. 

VAT registration number

What it is:

Your VAT number is the identifier for VAT-registered businesses.

Who gets one:

• Businesses that register for VAT

When you’ll use it:

• VAT invoices
• VAT returns and VAT-related admin
• Supplier and customer checks (for example, when confirming a VAT number is valid)

Where to find it:

After you register for VAT, you’ll receive a 9-digit VAT registration number and related information by post. You will also be able to find your VAT registration number on your submitted VAT returns, your online HMRC business tax account or by asking your accountant/bookkeeper.

You can also contact the HMRC VAT helpline: 0300 200 3700

PAYE Employer Reference Number (ERN)

What it is: 

Often called an Employer PAYE reference (or Employer Reference Number), this identifies an employer’s PAYE scheme with HMRC.

Who gets one:

• Employers who run payroll under PAYE

When you’ll use it:

• PAYE and payroll admin
• Employer-related forms and some third-party checks

Where to find it:

You can find your ERN on: your HMRC welcome pack, HMRC correspondence, employee tax forms, payslips or your HMRC online account. 

3. When and why you may be asked for a TIN

You’re most likely to see “TIN” wording when the person or organisation asking is using international terminology.

Common situations include:

• Opening a business bank account or applying for financial services where they need to identify the taxpayer or company
• Completing international forms (for example, where the form is designed for multiple countries and uses “TIN” as a catch-all term)
• Trading internationally or working with overseas platforms that expect a “TIN” field
• Compliance checks where a business or individual must be linked to an official identifier used for tax or legal registration

If you’re asked for a “TIN”, the quickest route is to work out whether they mean:

• a personal identifier (often NINO or personal UTR), or
• a business identifier (often company UTR, plus CRN if they also want registration details), or
• a context-specific identifier (VAT number for VAT, PAYE reference for payroll).

4. Where to find your UK tax ID

Here’s the simple “where do I find it?” list:

• UTR: On previous tax returns and other HMRC documents (like notices to file or payment reminders), and in your HMRC online account/app
• NINO: On documents you already have (for example, a P60 or payslip), and in your personal tax account or HMRC app
• CRN: On your company's certificate of incorporation/other official documents, the official Companies House register, or in correspondence from your accountant or formation agent.
• VAT number: On your VAT registration certification, submitted VAT returns, your online HMRC business tax account or by asking your accountant/bookkeeper.
• PAYE reference (ERN): On your HMRC welcome pack, HMRC correspondence, employee tax forms, payslips or your HMRC online account. 

5. Common misconceptions (and quick fixes)

“TIN number”

This is a common phrase, but it’s technically repetitive because TIN already means “Tax Identification Number”. (People still say it, and that’s fine.)

“UK TIN number.”

The UK doesn’t have a single TIN. Different identifiers apply depending on the taxpayer and context. 

“My NINO is the same as my company’s tax ID.”

No. A NINO is for individuals. A company is typically identified for tax by a company UTR, and legally by its CRN. 

“UTR and CRN are the same thing.”

No, they serve different purposes. CRN comes from Companies House and identifies the company on the register. UTR is used by HMRC to identify the taxpayer for tax matters.

“VAT and PAYE numbers are general tax IDs.”

This is incorrect; VAT and PAYE numbers are context-specific to VAT and payroll. You only have them if you register for those schemes.

6. What this means for UK companies and individuals

If you’re dealing with UK-only admin, you’ll usually be asked for the specific number the organisation needs, like “UTR” or “Company Registration Number”.

But when you’re dealing with international forms that ask for a “TIN”, use this simple rule of thumb:

• Employees/individuals: start with your NINO (unless the context clearly requires a UTR).
• Self-employed / Self Assessment: your UTR is often the right fit.
• Limited companies: your company UTR (tax) and your CRN are the core identifiers.
• VAT-registered businesses: use your VAT number for VAT documentation and checks.
• Employers running payroll: use your PAYE reference (ERN) for PAYE-related requests.

Getting this right matters because providing the wrong identifier can slow down onboarding, banking checks, registrations, or compliance steps.

Companies MadeSimple removes the guesswork from getting set up. With our company formation, registered office address, and VAT and PAYE registration services, your key business details are organised from day one, helping you move faster and stay compliant.

7. Conclusion

A “Tax Identification Number (TIN)” is an international label, not a single UK-issued number.

In the UK, your “TIN equivalent” depends on your situation: UTR, NINO, CRN, VAT number, or PAYE reference. Once you know which one you need, finding it is usually quick, because it will be on official documents and accounts linked to HMRC or Companies House. 

As a final practical tip: keep these numbers stored securely, and only share them with trusted organisations that genuinely need them.

If you’re setting up or managing a UK company, you can explore Companies MadeSimple’s services for company formation, registered office, and tax registrations to help keep everything simple and accurate from the start.

FAQ

What is a Tax Identification Number (TIN)?

A Tax Identification Number (TIN) is a general term for a number used to identify taxpayers. In the UK, there is not one single TIN. Instead, identifiers such as the Unique Taxpayer Reference (UTR), National Insurance Number (NINO) or Company Registration Number (CRN) are used depending on your tax or business status.

Does the UK have a TIN like other countries?

No, the UK does not issue a universal TIN. Different numbers act as TIN equivalents for individuals and businesses. Individuals use their National Insurance Number or UTR, while companies use identifiers such as a UTR, CRN or VAT number.

Which UK number counts as my tax ID if I am an individual?

If you are employed, your National Insurance Number acts as your tax ID. If you are self-employed or required to file a Self Assessment, you will also have a Unique Taxpayer Reference (UTR) issued by HMRC for tax purposes.

What number acts as a TIN for UK companies?

UK limited companies use their Unique Taxpayer Reference (UTR) for corporation tax and their Company Registration Number (CRN) for legal identification. Depending on the situation, a VAT number or PAYE reference number may also be used.

Where can I find my UTR, NINO or CRN?

• UTR: on HMRC documents and in relevant HMRC online accounts/services
• NINO: on payslips, P60s, and via your personal tax account/HMRC app
• CRN: on your certificate of incorporation and the Companies House register

Is my National Insurance number the same as a UK TIN?

It can be. For individuals, the National Insurance Number often acts as a TIN when dealing with HMRC. However, it is not universal. Companies and self-employed individuals generally use a UTR instead.

When might I be asked to provide a TIN in the UK?

You might be asked for a TIN when completing international forms, opening a bank or business account, registering for tax or trading abroad. In these cases, provide the relevant UK identifier such as your UTR, NINO or CRN.

Which number should I give when asked for a UK tax ID number?

It depends on your situation. Use your UTR if you are self-employed or run a company, your NINO if you are an employee, and your CRN if you are providing company registration details. Always confirm which number the requester needs.

If the UK does not have a single TIN, why do I see forms asking for one?

Many international systems use TIN as a universal term for taxpayer identifiers. UK residents and businesses should provide the closest equivalent such as a UTR, NINO, CRN or VAT number depending on the context.

Do I need a different number for VAT or PAYE?

Yes. Businesses registered for VAT or running payroll will have separate VAT registration and PAYE reference numbers. These are used for VAT reporting and employee tax purposes, not as general tax IDs.

Can non-UK residents get a UK tax identification number?

Yes. Non-UK residents who register a UK company or have UK-sourced income can receive a Unique Taxpayer Reference (UTR) from HMRC. This number identifies them for UK tax purposes and is often requested by foreign authorities.

How do I apply for a UK tax identification number?

You do not apply for a TIN directly. HMRC automatically issues a UTR when you register for Self Assessment or when a company is formed. National Insurance Numbers are issued when you start working or claim benefits in the UK.

Is my Company Registration Number the same as a UTR?

No. Your CRN identifies your business legally through Companies House, while your UTR identifies it to HMRC for tax purposes. Both are important but serve different functions.

What is the difference between a UTR and a VAT number?

A UTR identifies a taxpayer for general tax obligations, while a VAT number is used only for VAT-registered businesses. You might have both if your company meets VAT registration thresholds.

Should I keep my UK tax ID numbers confidential?

Yes. Treat your UTR, NINO and VAT numbers as confidential information. Share them only with HMRC, your accountant or trusted financial institutions to protect against identity theft or fraud.