Company Registration Number: What It Is and Where to Find It

You’re filling in a form — opening a business bank account, applying for insurance, signing up with a supplier — and it asks for your “company registration number”. You know you have one. You know it was in an email somewhere. But what actually is it, and where do you find it when you need it in a hurry?

What Is a Company Registration Number and Where Do I Find It?

A company registration number (CRN) is the unique 8-digit identifier Companies House assigns when your limited company is incorporated. It appears on your certificate of incorporation, in the email Companies House sent you, and on the public Companies House register — search your company name at find-and-update.company-information.service.gov.uk and it’s displayed prominently.

What It Looks Like

An 8-character code: usually 8 digits (e.g., 12345678), sometimes with letters for companies registered in Scotland (SC123456) or Northern Ireland (NI123456). It’s permanent — it never changes for the life of the company, even if you change the company name, address or directors.

Don’t confuse it with: your UTR (Unique Taxpayer Reference, 10 digits, issued by HMRC for tax), your VAT number (GB followed by 9 digits, only if VAT-registered), or your PAYE reference (for employers). Each is a different number from a different body, and forms ask for them separately. Mixing them up is one of the most common small-business admin errors.

Where to Find It (Fastest First)

1. Companies House website. Search your company name — the number is right there on the company overview page, free, no login. This works for anyone, including people checking your company.
2. Your certificate of incorporation. The PDF/email Companies House sent when you registered. Search your inbox for “certificate of incorporation”.
3. Official stationery. By law, your CRN must appear on your company’s letters, order forms, invoices and website. Check your own invoice template.
4. Your accountant. They have it on file. (This is also a good moment to ask why you don’t have it saved somewhere accessible.)
5. Previous filings. Any confirmation statement, annual accounts or HMRC correspondence shows it.

Save it in your phone notes, your password manager, and your accounting software today. You’ll need it constantly — bank applications, insurance quotes, supplier credit accounts, grant applications, tax filings. Future you will thank present you.

When You’ll Need It

• Opening a business bank account — the bank verifies it against Companies House
• Filing anything with Companies House or HMRC
• Invoices and official correspondence (legally required)
• Applying for credit, leases or supplier accounts
• Due diligence — customers and partners checking you’re legitimate

What Other People Can See

Your CRN is public information, along with your registered office address, directors’ names, and filed accounts. That’s by design — it’s how the system builds trust. But it’s worth knowing exactly what’s visible: search your own company on Companies House periodically to see what the world sees. If you used your home address as the registered office (common when registering a limited company), your home address is public. You can change to a service address later if that bothers you.

Checking Someone Else’s Company

The CRN is also your due-diligence tool. Before extending credit to a customer, signing a big supplier contract, or taking on a subcontractor: look up their CRN on Companies House. Check the accounts, the filing history, whether directors have a trail of dissolved companies. It takes five minutes and has saved countless businesses from bad debts. A company that hasn’t filed accounts in two years is waving a red flag.

The Bottom Line

Eight digits, permanent, public, and needed constantly — save it somewhere you can find in ten seconds. If you’re winding a company down rather than looking things up, our guide to closing a limited company with no debts covers that process. And for the official record of everything, the Companies House register itself is free and authoritative.

Company Registration Number: Questions, Answered

Is my company registration number the same as my UTR?

No — and mixing them up is the classic admin error. The company registration number (8 characters, from Companies House) identifies the company itself. The UTR (10 digits, from HMRC) is for tax. Forms ask for them in different boxes for different purposes: the CRN proves the company exists; the UTR links it to tax records. Save both, label them clearly, and you’ll never confuse them again.

Do sole traders have a company registration number?

No — sole traders aren’t registered at Companies House, so there’s no CRN. The equivalent identifier for a sole trader is the UTR issued by HMRC when you register for self-assessment. If a form asks a sole trader for a “company registration number”, leave it blank or write “N/A — sole trader”. Don’t invent one.

Can two companies have the same registration number?

Never. The number is unique and permanent — it’s never reused, even after a company is dissolved. That’s what makes it reliable for due diligence: a CRN identifies exactly one company across its entire history, regardless of name changes. If a “company” can’t produce a CRN that checks out on the Companies House register, treat it with extreme caution.

Where must I display my company registration number?

Legally, on: business letters, order forms, invoices, receipts, and your website. Practically, also have it ready for: bank applications, insurance, supplier accounts, grant applications, and contracts. Most businesses put it in the footer of their website and invoice template once, and never think about it again — until a form asks for it, when it’s right there.

Does the CRN change if the company changes its name?

No — never. The company registration number is permanent for the life of the company, through name changes, address changes, director changes and share restructures. That’s precisely what makes it useful: while names can be changed (and similar names can confuse), the CRN identifies exactly one company forever. When you’re checking out a supplier or customer, search by CRN rather than name — it’s the only identifier that can’t be muddied.