What Is a Company Registration Number?

Last updated: Sep 29, 2026 3 minute read Limited Company
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Daniel Tuckey
Written by: Daniel Tuckey

A company registration number (CRN) is a unique identifier issued by Companies House the moment your business is incorporated, and it stays with that company for its entire life. Anyone can use it to verify your company's existence, structure, and filing history on the public register.

Key Takeaways

  • A CRN is issued once, at incorporation, and never changes, even if you later change your company's name, address, or officers.
  • The format depends on where the company is registered: eight digits for England and Wales, or a two-letter prefix (such as SC for Scotland or NI for Northern Ireland) followed by six digits.
  • You're legally required to display your CRN on official company stationery, invoices, emails, and your website footer.
  • A CRN isn't the same as a UTR or VAT number, each serves a different regulatory purpose, so it's worth not confusing them.
  • Only limited companies and LLPs get a CRN. Sole traders and general partnerships don't, since they're registered with HMRC instead.

What Actually Is a Company Registration Number?

It's the number Companies House assigns to a company the moment it's incorporated, and it functions as that company's permanent legal identifier. Every UK limited company and LLP gets one, and it's sometimes referred to simply as a "company number."

Its main job is distinguishing one company from another, which matters more than it might sound, since company names can be genuinely similar without being identical. The CRN is what confirms which specific legal entity you're actually dealing with.

Why Does It Matter?

Beyond simply distinguishing your company from others, your CRN is what stakeholders, customers, suppliers, banks, and HMRC use to verify you're a genuine, currently registered company. It builds a basic layer of trust, and it's required on your official paperwork specifically so anyone dealing with you can independently confirm who they're doing business with.

What Format Does a CRN Take?

It depends on where the company is registered. Companies registered in England and Wales typically have an eight-digit number. Companies registered in Scotland use the prefix "SC" followed by six digits, and Northern Ireland uses "NI" the same way. Recognising the correct format for your company helps avoid confusing it with an unrelated number, like your UTR or VAT registration number, both of which serve entirely different purposes.

Do I Need to Display My CRN Anywhere?

Yes, it's a legal requirement to show it on official company stationery, letterheads, invoices, emails, and your website, typically in the footer. This isn't just a formality: it's there specifically so anyone dealing with your company can verify it independently, and failing to display it can lead to compliance issues.

Does My CRN Ever Change?

No, never. It stays exactly the same for the life of the company, regardless of a name change, a change of registered office, or new directors being appointed. It's tied permanently to the legal entity itself, not to any of its changeable details.

Where Do I Find My Company's Registration Number?

Your Certificate of Incorporation is the quickest place to check, along with your account if your company was formed through a formation agent, or directly via the Companies House website. Our full guide to finding your company registration number walks through each option in detail.

FAQs

What is a company registration number (CRN)?

A unique identifier issued by Companies House to every incorporated UK company, staying with it for the company's entire life and confirming its legal identity.

Who needs a company registration number, and who doesn't?

Every limited company and LLP registered with Companies House gets one. Sole traders and general partnerships don't, since they're registered with HMRC instead.

What format does a UK company registration number follow?

Eight digits for England and Wales companies, or a two-letter prefix, such as "SC" for Scotland or "NI" for Northern Ireland, followed by six digits.

When and why must I display my company registration number?

On all official stationery, invoices, your website, and any promotional material showing company details, as a legal requirement demonstrating transparency and compliance.

Can my company registration number change if I change the company name or address?

No, it stays the same throughout the company's life, regardless of changes to its name, address, or officers.

How is the company registration number used in everyday business tasks?

You'll need it when filing annual accounts, submitting a Confirmation Statement, registering for Corporation Tax, and setting up a business bank account, among other official processes.

This article is for general information only and does not constitute legal advice. Companies House requirements can change, so it's worth checking current guidance on GOV.UK or Companies House before relying on the details above.