HMRC Tax Identification Number (TIN) Simplified!

Last Updated: May 23, 2024
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🔑 Key Takeaways

  • The taxpayer identification number (TIN) is a unique combination of letters and/or numbers used to identify an individual for tax purposes.
  • Within the context of the UK, unique taxpayer reference numbers, employee reference numbers, company registration numbers, VAT, and national insurance numbers are all tax identification numbers since they serve different purposes within the UK tax system.

What is a tax identification number UK?

Tax identification number (TIN) is a term used to refer to numbers that are used to identify individuals or companies for domestic and international tax administration and compliance. A TIN number in the UK may refer to –

  • A unique Tax Reference number (UTR) is a 10-digit number that HM Revenue and Customs (HMRC) issues to individuals and companies.

  • VAT registration numbers issued by HMRC to eligible companies.

  • Employer Reference Number (ERN), or employer PAYE number, is issued to entities registering with HMRC as employers to report salaries and tax deductions.

    ERN is essential for various employment-related processes, such as tax returns and buying business insurance. It is typically found on tax forms, payslips, P45s, P60s, or P11Ds issued to past or present employees and in correspondence from HMRC about PAYE.

  • A Company Registration Number (CRN) is issued by Companies House upon incorporation.

  • The National Insurance Number (NINo) is issued by the Department of Social Development (DSD) in Northern Ireland at the age of 16 and by the Department for Work and Pensions (DWP) in England, Scotland, and Wales

According to GOV.UK, a national insurance number, ensures your insurance contributions and taxes are recorded against your name only. It’s made up of letters and numbers and never changes.

In other jurisdictions outside the UK, TIN may mean the social security number, citizen or personal identification code, or resident registration number.

What is the process of obtaining a TIN?

Once you’ve identified the need for a TIN, obtaining one involves determining your appropriate taxpayer classification.

For individuals, this might involve considering factors such as employment status, while companies may need to assess their legal structure and activities. After establishing the taxpayer classification, the next critical step is identifying the relevant authority responsible for issuing the specific type of TIN needed.

To make an application, individuals must provide information such as their full legal names and date of birth. At the same time, business submit their company name, CRN, and any other relevant company registration information.


People who are not liable to pay tax or national insurance, are below 16 years old, and do not have the right to work in the UK are not eligible for TIN. Furthermore, people over pension age who are neither working nor claiming benefits cannot get a NINo.

How Companies Obtain TIN Numbers

For business, the process will vary depending on whether you are a limited company, sole trader, or a limited liability partnership.

LTDs require a UTR and a CRN to identify them for tax affairs. These essential numbers are seamlessly allocated when you register your business as a limited company, eliminating the requirement for additional submissions beyond the standard company registration documents.

Quick Info

Unlike LTDs, sole traders and LLPs operate as individuals for tax purposes. Therefore, they must register for self assessment to obtain their taxpayer identification numbers. To register, you’ll need to create a Government Gateway account with HMRC.

Businesses and other entities can register for an ERN before an employee’s first payday. While processing an application typically takes up to 15 working days, it is advisable not to delay registration if there are plans to hire an employee within the next two months. provides two registration options, one for a limited liability company with 1 to 9 directors and another for every type of business.

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How Individuals Obtain UK TIN Numbers

Regarding NINo, most citizens automatically get their number 3 months before their 16th birthday if their parent filed for the Child Benefit claim. If a citizen doesn’t get it by their 19th birthday, then they’ll need to make an application.

Quick Info

GOV.UK highlights, you can apply for an NI number if you live in the UK, have the right to work in the UK, are working, are looking for work, or have an offer to start work. You can begin to work before you receive your NINO if you can prove you have the right to work in the UK.

For further details on the adult registration process, see:

Purpose and functions of TIN?

Within the United Kingdom, TINs play a multifaceted role in the country’s tax system. It helps identify taxpayers, monitor tax obligations, and streamline government tax administration processes.

Here is how each number serves its purpose –

  1. Individual and Corporate UTR

    UTR is a crucial number for tax management in the uk issued to self-employed individuals and companies by HMRC to identify them for taxation. Here is how it is useful:

    For self-employed individuals:

    • Required to file tax returns;

    • Needed for self-assessment, tax obligations, and when engaging in business activities;

    For Companies, a UTR is used to:

    • Identify the company for corporation tax obligations, such as filing VAT and corporation returns and managing respective payments;

    • Register for VAT once an entity becomes eligible;

    • Register for PAY and the Construction Industry Scheme (CIS);

    • Tell HMRC that your business is inactive and to file dormant company accounts and

    • For any correspondence with tax authorities.

    According to the guidelines of, you can find your utr number in your Personal Tax Account in the HMRC app under ‘Your details’ or in the ‘Self Assessment’ section or on previous tax returns and other documents from HMRC (for example, notices to file a return or payment reminders).

    Read: Company UTR Number Explained

  2. The Company Registration Number (CRN)

    CRN is a distinctive alphanumeric code comprising either 8 numbers or 2 letters followed by 6 numbers. The unique identifier is prominently featured on the certificate of incorporation, any correspondence you receive from Companies House, and in their public register of companies.

    As an identifier, the number is referenced in —

    • Filing confirmation statements or annual company accounts;

    • Registering for VAT and PAYE;

    • Official correspondence with government agencies, suppliers, banks, partners, employees, and other stakeholders; and

    • Issuance of share certificates or return of allotment of shares.

    The number is also used in business stationery, including letterheads, websites, and invoices.

  3. National Insurance Number

    It is also an alphanumeric code, comprising 2 letters, 6 numbers, and a final letter, designed to enhance the uniqueness and security of each NINo, allowing for accurate identification of individuals in various government and social security-related processes. However, NINo cannot serve as proof of identity or right to work.

    The number is used for —

    • National Insurance Contributions (NICs) and Tax Record;

    • Employment and Benefit Claims;

    • Student loan applications;

    • Payment of tax on Personal Equity Plans and Individual Savings Accounts (ISA); and

    • The UK tax agency, government departments, and financial service providers use it to verify the identity of individuals and administer state benefits.

    To find your NI Number, check your payslip, P60, any official correspondence relating to tax, pensions, benefit payments, or your online tax account.

    Initially, HM Revenue and Customs issued temporary reference numbers to adults who did not have NINo. However, presently, per information provided by, an employer dealing with an employee who doesn’t have a NINO should keep a record of their full name (surname and first name(s)), address, date of birth, and gender, and tell them to contact DWP on 0800 141 2075.

  4. PAYE

    Once you register, you’ll receive your employer identification number, a two-part alphanumeric number with letters and numbers. It has three numerical digits, followed by a forward slash “/,” and then two letters, and finally, it ends with four numerical digits, something like this: 123/AB4567.

    Its purpose and functions include —

    • Identify a business for tax and link it to a nearby HMRC national office, which is determined by the entity’s geography or industry.

    • Required for statutory reporting obligations such as PAYE payments and returns; and

    • Used as a security check when accessing tax information.

    You’ll find your PAYE on various documents, including HMRC correspondence, payslips, P45s, P60s, or P11Ds.

What is the difference between a TIN and the National Insurance Number within the UK tax system?

TIN is a broad term for different numbers used within the UK tax system to identify individuals and entities for taxation or insurance contributions.

Quick Info

The insurance number, therefore, is a subtype of TIN, signifying one of the several identification numbers employed within the system. Everyone above 16 with the right to work in the UK or wishing to pay voluntary class 3 NICs must get the number.

What Is the UK alternative to a tax identification number?

In the UK, the equivalent of a TIN encompasses various identifiers, including the Unique Taxpayer Reference (UTR) number, National Insurance Number (NINo), Company Registration Number (CRN), PAYE reference, and VAT registration.

To ascertain the precise TIN you need, you’ll have to carefully evaluate the nature of your financial activities, business structure, and tax obligations, as each of these identifiers serves a distinct purpose in the UK taxation system.

For instance, the UTR number is often associated with personal and business tax matters, while the CRN is tied to company registration and dealings with Companies House. On the other hand, NINO is more focused on individual contributions to the National Insurance system.

What is the difference between TIN and UTR?

Strictly speaking, there is no distinction between a UK TIN and a UTR since the latter is a specific subtype of a tax identification number narrowly used to reference individual or business taxpayers in the UK. Consequently, depending on the context, these terms are occasionally used interchangeably.

Article by

Fridar Gichuki

Fridar Gichuki is a lawyer by training turned dedicated content writer & strategist. She brings over 10 years of experience leveraging her legal acumen to support and inspire small businesses on legal, finance, and marketing topics. When not immersed in the world of content, you'll find her hiking across vast plains and scaling high mountains.


  1. John Mills

    I need to find my TIN, how do i do this?

    • Your Company Formations

      Hi John,

      Thanks for reaching out!

      In the UK, a Tax Identification Number (TIN), could be any of the following, depending on your situation:

      1. UTR Number – You can find this in your HMRC app under ‘Your details’ or in the ‘Self Assessment’ section. It’s also on previous tax returns or documents from HMRC.

      2. VAT Registration Number – If your business is VAT registered.

      3. ERN (Employer Reference Number)- Look for this on tax forms, payslips, P45s, P60s, or in correspondence from HMRC about PAYE.

      4. CRN (Company Registration Number)- Issued by Companies House when you incorporate your company. You’ll find it on your certificate of incorporation.

      5. NINo (National Insurance Number)- If you don’t have one, you can apply if you live and work in the UK.

      Hope this clears things up! Let us know if you have any more questions.


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