A CRN (company registration number) is the unique number Companies House gives every company when it is incorporated. For a company registered in England and Wales it is usually 8 digits, often starting with zeros, such as 01234567. Companies registered in Scotland and Northern Ireland have a two-letter prefix ("SC" or "NI") followed by six digits. You will find it on the certificate of incorporation and on the free Companies House register. By law it must appear on the company's business letters, order forms and website. It is not the same as the company's 10-digit tax reference (UTR) or its VAT number.
What the company registration number is
Section 1066 of the Companies Act 2006 requires the registrar to give every company "a number, which shall be known as the company's registered number". The format is set by the registrar. HMRC's own guidance describes it as "up to eight numerals or normally two alphabetical characters referred to as the prefix followed by up to six alphanumeric characters". In practice:
- England and Wales companies. Eight digits, with leading zeros on older companies;
- Scottish companies. "SC" followed by six digits;
- Northern Ireland companies. "NI" followed by six digits;
- Other entities. LLPs, foreign companies with a UK establishment, and some other bodies on the register carry their own two-letter prefixes.
The number is the company's permanent identifier. It stays the same when the company changes its name or moves its registered office. That is why HMRC, banks and credit agencies key their records to it rather than to the name. Only the registrar can change the format of registered numbers, and the Act allows either the old or new number to satisfy disclosure rules for three years after any change.
How to find a company's CRN
- Companies House register. Search by company name on the free Find and update company information service. The number appears next to every result and at the top of the company's page, along with its filing history, officers and registered office;
- Certificate of incorporation. The certificate states the company's name and registered number, its date of incorporation, whether it is limited by shares or by guarantee, whether it is private or public, and whether its registered office is in England and Wales, Wales, Scotland or Northern Ireland;
- The company's own paperwork. Letters, invoices, order forms and websites must show it, so a supplier's invoice or the footer of its website is usually the quickest place to look;
- Companies House correspondence, such as filing reminders and confirmation statement notices.
Checking the CRN of a customer or supplier against the register is a basic due diligence step. It confirms the company exists, is active, and is the entity named on the contract, not a similarly named one. It also shows whether accounts and confirmation statements are overdue, which can be an early warning sign.
The same logic applies to your own contracts. Names are not unique in everyday use: a group may have a dozen companies with similar names, and an unrelated business may trade under a name close to yours. Quoting the full registered name together with the CRN in contracts, guarantees and purchase orders removes any doubt about which legal entity is bound. It is the CRN, not the trading name, that a court, lender or liquidator will rely on.
Where a company must show its CRN
The Company, Limited Liability Partnership and Business (Names and Trading Disclosures) Regulations 2015 require every company to disclose three particulars on its business letters, order forms and websites:
- the part of the United Kingdom in which it is registered;
- its registered number;
- the address of its registered office.
In practice, that means letterheads, order forms, and a footer or legal page on the website. If the company chooses to state its share capital, it must state the paid-up capital, not just the authorised or nominal figure. Getting this wrong is a breach of the regulations. It also makes the company look less established to anyone who checks.
CRN, UTR, VAT number and authentication code: what is the difference?
| Number | Issued by | Format | Used for |
|---|---|---|---|
| Company registration number (CRN) | Companies House | 8 characters (e.g. 01234567, SC123456) | Identifying the company on the public register and in contracts |
| Unique Taxpayer Reference (UTR) | HMRC | 10 digits | Corporation tax returns and correspondence |
| VAT registration number | HMRC | Issued on VAT registration | VAT invoices and returns |
| Company authentication code | Companies House | 6-character alphanumeric | Authorising online filings: the equivalent of an officer's signature |
The CRN is public, and the UTR and authentication code are not. HMRC posts the Corporation Tax UTR to the company's registered office address after incorporation. When you register for corporation tax, HMRC asks for the company registration number to link the two records (see our guide to corporation tax). The authentication code is sent by post to the registered office and can take up to 10 working days to arrive. It should be guarded like a signature, because anyone holding it can file on the company's behalf. It is also different from the personal code each director receives after verifying their identity with Companies House, which applies to the individual, not the company.
Common questions
- Can a sole trader have a CRN? No. Only entities registered at Companies House, such as companies and LLPs, have one. A sole trader has a personal UTR from HMRC;
- Is a CRN the same as a company number? Yes. "Company number", "registered number" and "company registration number" all mean the same thing;
- Do I need to apply for one? No. It is allocated automatically on incorporation and printed on the certificate.
Acumon's company secretarial services keep registered details, disclosures and Companies House filings in order. Our company formation team handles new incorporations from name check to certificate (see also how to check a company name).