GOV.UK Company Registration Number (CRN Number) Explained!

Last updated: March 27, 2026 5 min read

Magnifying glass over the GOV.UK website homepage used to find a company registration number on Companies House

Written by: Robert Carter

UK Company Formation and Compliance Adviser

Key Highlights

A CRN number is a unique identifier issued by Companies House when you incorporate a business. It can be an 8-digit number or a combination of letters and digits, varying by location and type of company.
The number appears on your certificate of incorporation and statutory mail. Legally, it must be displayed on all business stationery, including invoices and emails.
Use your registration number for official tasks such as communicating with Companies House, filing annual returns, changing company details, and managing taxes. Avoid confusing it with other numbers like your VAT or Unique Taxpayer Reference (UTR).

What Is a Company Registration Number?

A Company Registration Number (CRN), also known as a “Companies House Number” or “Company Number,” is a unique identifier assigned to limited companies and LLPs when they are registered with Companies House. While company names can share similar words or phrases with other businesses, the CRN is unique and valid for the life of the company, and no two companies will have the same number.

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What is the format of a Company Registration Number?

A CRN is a unique identifier for UK companies. It is typically 8 characters long, 8 digits or 2 letters followed by 6 digits.

Eight digits (e.g., 12345678)
Two letters followed by six digits (e.g., AB123456)

However, the exact format can vary depending on the location and type of company:

8-digit number: Companies formed in England and Wales
“OC” prefix: LLPs in England and Wales
“LP” prefix: Limited Partnerships in England and Wales
“SC” prefix: Companies formed in Scotland
“SO” prefix: Scottish Limited Liability Partnerships (LLPs)
“SL” prefix: Scottish Limited Partnerships
“NI” prefix: LTDs in Northern Ireland
“NC” prefix: LLPs in Northern Ireland
“NL” prefix: Limited Partnerships in Northern Ireland

Do sole traders and partnerships need a company registration number?

Sole traders do not receive CRNs because they register with HMRC rather than Companies House. Similarly, general partnerships, also known as ordinary partnerships, do not have a business identification number as the registrar of companies does not incorporate them.

Only a limited company or limited liability partnership are given a company registration number.

How do I find your company registration number?

There are a few places where you can locate your CRN:

Certificate of incorporation: Once you set up a limited company, you will find your CRN in the registration certificate.
Companies House correspondence: Look for your CRN on any official mail from Companies House. It’s usually printed alongside or beneath headings like “Company No.”
Correspondence from advisors: Communications from advisors, such as your company formation agent or accountant, may also include your CRN.
Online public register: You can find your company identification number through the Companies House Search service by following the steps below.

Step 1: Visit https://find-and-update.company-information.service.gov.uk/

Screenshot of the Companies House search the register page where you can look up a company registration number by name or officer — Screenshot of the Companies House online register search page.

Step 2: To search for a company, enter its name in the search box.

Step 3: Click the “SEARCH” button. You’ll see a list of all UK companies with names that match yours, in part or full. For instance, if your company is named “GreenTech Solutions,” the search results might include similar names like “GreenTech Innovations,” “GreenTech Services,” or “EcoGreenTech Solutions.” The list will include the registered office addresses to help you identify and select the correct company.

Step 4: Click on the company of interest.

Step 5: The CRN is below the company name and is labelled “Company Number.”

Screenshot of Your Company Formations Ltd on Companies House showing the company registration number 09094616 highlighted beneath the company name — Example of a Companies House record showing the CRN under the company name.

Where should I display my company registration number?

Your CRN is a crucial element of your business identity. As a limited company, the law requires that you display the number on all official business stationery and communication. This helps to ensure transparency and compliance with UK company law.

You should include it in the following official company stationery:

Letterheads: On all official letters your company sends.
Emails: Every email, especially related to business transactions, should have your it in the footer.
Invoices: It must be displayed on all invoices to maintain legal compliance and ensure transparency.
Receipts: Receipts issued by your company should also include it.
Online Content: The number should be prominently displayed in the footer of your website and on key pages like the “Contact” or “About Us” sections.
Order Forms: Any order forms your business uses should include the registration number to ensure legal compliance.

By consistently displaying your registration number on these items, you comply with legal requirements and present a professional and credible image to clients, partners, and stakeholders.

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Your CRN is distinct from other essential business identification numbers your company may have, such as:

VAT Number: A value-added tax identification number issued by HMRC to every company registered for VAT. It’s used for VAT reporting and invoicing.
Company UTR Number: HMRC issues new companies in the UK with a 10-digit unique taxpayer reference (UTR) number for tax-related purposes.
EORI Number: Businesses importing or exporting goods within or outside the European Union must have an Economic Operators Registration and Identification (EORI) number.
DUNS Number: The Data Universal Numbering System (DUNS) number is a unique identifier for businesses used internationally to establish business credit and manage risk.
PAYE Reference Number (ERN Number): HMRC provides an employer reference number, which is used for payroll and PAYE (Pay As You Earn) submissions.
Accounts Office Reference (AORN): This is another number HMRC issued for PAYE payments. It identifies the employer’s payroll account.
Companies House WebFiling Authentication Code: This unique 6-character alphanumeric code provided by Companies House allows you to file and access company records online.
Tax Identification Number UK (TIN): Unique numbers like the Unique Taxpayer Reference (UTR), National Insurance Number (NINo), Company Registration Number (CRN), VAT Registration Number, and PAYE reference, used to identify individuals and businesses for tax and compliance purposes.
Right to work share code: A secure and convenient way for workers to share their immigration status with potential or current employers. It ensures compliance with UK employment laws.

Can I use a CRN to discover the previous company name of a business?

You can use a company number to determine a business’s previous name. When you search using the CRN, the search results will display only the company associated with that unique registration number. After selecting the company, scroll down the page, and you will find a section that lists any previous names the company has used.

Article byRobert Carter

Robert Carter is a business adviser with deep experience in UK company formation, corporate compliance, and SME strategy. At Your Company Formations, he provides senior oversight of all content and services, ensuring accuracy in line with current Companies House standards, HMRC requirements, and UK company law. He works with founders, directors, and international entrepreneurs navigating the UK business landscape.