A company registration number, commonly abbreviated to CRN, is the unique number assigned to a company when it is incorporated and registered with Companies House. It is an identifier for the legal entity in the Companies House system and is distinct from the company's name, registered office, VAT number, PAYE reference and Corporation Tax Unique Taxpayer Reference. The number is issued as part of the incorporation process and appears on the certificate of incorporation. GOV.UK states that the certificate confirms that the company legally exists and shows the company number and date of formation. The number is therefore a fundamental identifier of the incorporated company rather than a number describing the business's turnover, tax liability, industry or ownership.
The CRN is particularly useful because a company name can change while the underlying legal entity and company number remain associated with the same company, subject to the relevant Companies House records. It therefore provides a more stable way of identifying a particular corporate entity than relying solely on its current name.
Public company information can be searched using the company number or company name, and Companies House records can include the company's registered office, officers, filing history, accounts and other statutory information. If two companies have similar names, the CRN provides an unambiguous identifier for the particular entity being discussed. This is why businesses, professional advisers, banks, suppliers and official bodies commonly use the company number when referring to a specific incorporated organisation.
The number should not be confused with other identifiers. A VAT registration number identifies a business for VAT purposes; a Corporation Tax Unique Taxpayer Reference identifies the company within HMRC's tax system; a PAYE reference relates to an employer's payroll arrangements; and a Companies House company number identifies the registered corporate entity. A company can therefore have several different numerical identifiers at the same time.
A sole trader does not receive a Companies House company registration number simply because they register for Self Assessment, because the sole trader is not incorporated as a separate company. Similarly, having a VAT number does not prove that a business is a limited company. The context in which a number was issued must therefore be established before interpreting it.
Company registration numbers are jurisdiction-related identifiers. Companies House operates registers for companies incorporated in England and Wales, Scotland and Northern Ireland, and the format or prefix of a number can provide clues about the jurisdiction or registration history. The exact format should not be interpreted as a universal code for company size or legal status. A company number can remain with the entity even when its registered office, directors, shareholders or business activities change, subject to statutory filings. Companies incorporated outside the UK may have different registration systems and numbers, so the expression “company registration number” is not globally standardised. In international transactions, it is important to identify which country's corporate registry issued the number.
The CRN is shown on official company records and the certificate of incorporation and can be used to locate the company's Companies House record. The public record contains information about the company, including its registered office, directors, persons with significant control, filing history and other statutory information. This makes the number useful when verifying that a supplier, customer or contracting party is the company they claim to be.
It can also help distinguish a company from a similarly named business or trading name. However, finding a valid company number does not by itself prove that the company is financially sound, reputable, authorised to provide a particular regulated service, or actually operating under the brand name being presented to a customer. Those are separate verification questions.
A company registration number is also important in legal and commercial documentation because the incorporated entity should be identifiable precisely. Company invoices, contracts, websites and other corporate communications often include the legal company name and registration number so that counterparties can establish who the contracting party is. This is especially important where a business operates under a trading name that differs from its registered company name.
A customer may interact with a brand but legally contract with a company whose registered name is different. The company number provides an additional identifier that connects the commercial brand to the underlying corporate entity. The exact disclosure requirements for company documents depend on the relevant company-law rules and circumstances, so businesses should ensure their corporate stationery and website information comply with applicable requirements.
The number is created through incorporation and is not something an entrepreneur chooses. When Companies House accepts an incorporation application, it assigns the company its registered number and records the entity on the public register. The certificate of incorporation states the registered number alongside the company name, incorporation date and other fundamental information. Companies House data systems can also use the company number as a unique identifier in machine-readable company information, demonstrating its role as a stable reference within the registry.
In practical terms, if someone asks for a UK limited company's “company registration number”, they normally mean the Companies House company number. It should be obtained from the company's official Companies House record or incorporation certificate rather than copied from an unverified third-party directory. A company name can be searched on the Companies House service and the resulting record can be checked against the company's claimed legal identity. The number is best understood as the corporate equivalent of a registry identifier: it tells the user which particular incorporated entity the public record describes. It does not, by itself, describe the company's tax position, financial health, ownership quality or commercial performance.
