What Is a Company Number and How to Find One

What is a company registration number (CRN)?

A company registration number, often shortened to CRN, is the unique identifier that Companies House assigns to a business when it is incorporated. It stays with the company for its entire life and never changes, even if the company changes its name, moves address, or alters its directors. Because it is unique, the CRN is the most reliable way to identify a specific business, especially when several companies share a similar trading name. Sole traders do not have a CRN, as they are not registered at Companies House — only incorporated entities such as private limited companies and LLPs receive one.

What does a UK company number look like?

For a company registered in England and Wales, the CRN is an 8-digit number, such as 12345678. Companies registered in Scotland use the prefix "SC" followed by six digits (for example SC123456), and those registered in Northern Ireland use the prefix "NI" followed by six digits. You may also see prefixes such as "OC" for limited liability partnerships in England and Wales, or "SO" for LLPs in Scotland. Whatever the format, the number is always exactly eight characters long and is shown on every official record for the company.

Where can you find a company number?

There are several reliable places to look. The quickest is to search the public register on Companies House, or simply look the company up here on BizLookup. The CRN also appears on the certificate of incorporation issued when the company was formed, on official letters and invoices, and frequently in the footer of the company's own website alongside its registered office address. UK companies are legally required to display their registered number on business letters, order forms, and their website, so it is rarely difficult to track down once you know where to look.

CRN vs VAT number vs UTR

It is easy to confuse the different reference numbers a business holds, but they serve very different purposes. The CRN is issued by Companies House and identifies the company on the public register. A VAT number is issued by HMRC only to businesses that are registered for VAT, and it is used for charging and reclaiming VAT — you can read more in our guide on how to find a company VAT number. A Unique Taxpayer Reference, or UTR, is a 10-digit number also issued by HMRC and used for tax and Corporation Tax purposes; unlike the CRN, the UTR is confidential and is not shown on the public register. In short, the CRN is public and permanent, the VAT number applies only to VAT-registered businesses, and the UTR is private.

How to look up a company on BizLookup

BizLookup makes it straightforward to find any UK company, whether you know its number or only its name. If you have the CRN, you can enter it directly to jump straight to the correct record without any ambiguity. If you only have the name, you can search and browse matching results, then open the one you need to confirm its details — our guide on how to check a company walks through this step by step. From the company record you can see the registered office, incorporation date, status, and other key information drawn from the public register, all from a single page on our homepage.

Why do you need a company number?

You will need a CRN in many everyday business situations: opening a business bank account, filing accounts and confirmation statements, signing contracts, applying for credit, and carrying out due diligence on a supplier or customer. Because it uniquely and permanently identifies a business, the CRN is also the foundation for verifying that a company genuinely exists and is in good standing before you do business with it. If you are building prospect lists or screening multiple companies at once, you can use our lead lists to work with verified company data at scale rather than checking each number by hand.