Every limited company registered in England, Wales, Scotland, or Northern Ireland has a unique company registration number assigned at incorporation. If you need to verify a supplier, complete a credit check, or fill in a Google Ads billing form, knowing how to find company registration number quickly will save you real time.
Your company registration number is a permanent identifier issued by Companies House — it appears on your certificate of incorporation, your statutory filings, and is freely searchable on the Companies House register.
How to Find Company Registration Number on Companies House
The fastest and most reliable method is the Companies House register, which is free to use and publicly accessible without an account. Type the company name into the search bar and the registration number appears immediately alongside the company's registered address and filing history.
The company registration number (also called a CRN or company number) is always either eight digits long, or two letters followed by six digits for certain company types. Scottish companies begin with SC, Northern Irish companies begin with NI, and limited liability partnerships use OC as a prefix. Knowing the format helps you spot errors instantly when you receive a number from a third party.
If you are searching for a company you have a relationship with — a supplier, client, or contractor — the name search is usually sufficient. Where names are similar or the company has changed its trading name, use the registered address or director name filters to narrow results. Companies House indexes every active and dissolved company, so the record will be there even if the business is no longer trading.
One thing worth flagging from our nine years running a marketing agency: clients would regularly confuse their company registration number with their VAT number. They are different. Your VAT number is issued by HMRC, begins with GB, and is only relevant for VAT-registered businesses. The CRN is issued by Companies House, has no GB prefix, and applies to every incorporated entity regardless of VAT status.
Where Else to Find Your Company Registration Number
If you are looking up your own number rather than a third party's, there are several places it appears without needing to search the public register.
Your certificate of incorporation is the most authoritative source. Companies House issues this digitally when you incorporate, and it states the number prominently at the top. If you incorporated through a formation agent, they will have sent you this document either as a PDF or a printed certificate.
Beyond the certificate, the number appears on every piece of official correspondence from Companies House, including reminder letters about confirmation statements and accounts filing deadlines. It also appears on your company's statutory registers, and — importantly for compliance purposes — it should appear on your company letterhead, email footer, and website if you are a limited company. This is a legal requirement under the Companies Act 2006, not optional.
Business bank accounts frequently display the CRN in the account details section, particularly with challenger banks like Starling and Tide that integrate company data at onboarding. Your accountant's records and any contracts signed by the company as a legal entity will also carry the number.
| Where to look | Best for | Cost | Speed |
|---|---|---|---|
| Companies House register | Any company, third-party searches | Free | Instant |
| Certificate of incorporation | Your own company | Free | Depends on where you stored it |
| Companies House WebFiling portal | Your own company (logged in) | Free | Instant |
| Companies House letters / reminders | Your own company | Free | Only when correspondence arrives |
| Business bank account dashboard | Your own company | Free | Instant |
| Your accountant | Your own company | Free (usually) | Depends on response time |
Why the Company Registration Number Matters for Business Admin
Understanding how to find company registration number is not just a one-off task. It comes up repeatedly across business operations, and having it memorised or stored accessibly is worth the thirty seconds it takes.
For credit applications, supplier onboarding, and contract execution, the CRN is a standard field. It allows the other party to run a credit check via Companies House or a bureau like Creditsafe, verify your legal status, and confirm that the entity they are contracting with genuinely exists. This is the same reason sole traders, who are not incorporated, do not have a CRN — they are not registered companies.
For Google Ads accounts specifically, the CRN occasionally appears in billing and verification contexts, particularly if you are setting up a manager account or responding to a billing dispute. If you are running ads through a manager account under a third-party agency or AI agent, the underlying advertiser details — including company information — need to be accurate and consistent. See our guide on Google Pay Per Click Management: What SMEs Need to Know for more on how advertiser account structure works in practice.
Tax returns, VAT submissions to HMRC, and Companies House filings all reference the CRN. If you ever need to restore a dissolved company or challenge a strike-off notice, the CRN is the primary identifier used throughout that process.
How to Find a Company Registration Number for a Third Party
Searching for another business's registration number — perhaps to verify a potential supplier or due-diligence a partner — follows the same Companies House process, but there are a few additional considerations.
If the company name is common or has multiple exact matches, look at the registered address and incorporation date to confirm you have the right entity. A company registered in 2019 at a Sheffield address is unlikely to be confused with one registered in 2003 in Croydon, even if the names are identical. Companies House shows both active and dissolved records, so verify the status before concluding anything about the business's current standing.
For deeper checks beyond the registration number — including director history, charges registered against the company, or persons of significant control — Companies House provides all of this free of charge within the same company profile. Credit reference agencies like Creditsafe or Experian Business pull from the same underlying data but package it into formatted reports, which is useful if you need a PDF for internal approval processes.
If you operate internationally, note that the Companies House register only covers UK-incorporated entities. For Irish companies, the equivalent is the Companies Registration Office (CRO). For EU companies, each member state has its own national register, though the EU Business Register portal links to many of them.
Company Registration Number Format and Validation
Knowing the correct format helps you validate numbers you receive from counterparties without running a full search. A UK company registration number follows predictable rules depending on the company type.
England and Wales private limited companies: eight digits, often with leading zeros (e.g. 01234567). Scottish companies: SC followed by six digits. Northern Ireland: NI followed by six digits. Limited liability partnerships: OC followed by six digits. Limited partnerships: LP followed by six digits. Royal Charter companies and community interest companies have their own prefixes, though these are less commonly encountered in day-to-day business.
If someone hands you a seven-digit number with no prefix, it is likely a private limited company where the leading zero has been dropped — this is a common formatting error, not necessarily fraud. Pad it to eight digits and run the search to confirm.
One opinion worth stating clearly: we have seen businesses, particularly small ones that incorporated recently, genuinely not know their own CRN. This is less about negligence and more about the fact that formation agents and accountants handle everything at setup, and the owner never needs to look at the paperwork again until something goes wrong. Store your CRN somewhere accessible — a shared password manager, a pinned note in your accounting software, or a saved document in your company admin folder. It will come up more often than you expect, especially as you grow and take on more formal business relationships.
If your goal right now is to tighten up your business admin so you can focus on growth — including making your Google Ads budget work harder — see how Overtime manages ad accounts for SMEs. It handles bid adjustments, pauses underperforming keywords, and reallocates budget automatically, with weekly summaries so you always know what is happening.
What to Do If You Cannot Find the Registration Number
Occasionally a search returns no result. There are a few explanations, and knowing how to find company registration number in edge cases is useful.
The most common reason is a name discrepancy. Companies are registered under their legal name, which may differ from their trading name. A business trading as "Blue Sky Marketing" might be legally registered as "BSM Digital Solutions Ltd". If the name search fails, try searching by registered address or director name instead.
A second reason is that the company may not be incorporated at all. Sole traders, partnerships, and unregistered charities do not appear on the Companies House register because they have no CRN. This is not a red flag in itself, but it does mean that any credit checks or formal due diligence will need to follow a different process.
Third, very recently incorporated companies can take 24 hours to appear in the searchable register after the digital certificate is issued. If you incorporated yesterday, check again tomorrow.
For your own Google Ads management and the business admin that surrounds it, having your company details accurate and accessible matters. Our guide on how much Google Ads costs for SMEs is worth reading alongside this if you are at the point of setting up or reviewing your advertising accounts.
Knowing how to find company registration number is one of those foundational admin tasks — simple when you know where to look, frustrating when you do not. The Companies House register answers the question in under a minute for any UK-incorporated entity, free of charge, with no login required.
If you are getting your business admin in order before scaling your advertising spend, the next logical step is making sure your Google Ads account is working as efficiently as your admin processes. Overtime's approach to Google Ads management is worth reviewing — it is built specifically for SMEs who want professional-grade ad management without the overhead of a full agency relationship. And once your accounts are running, see what Overtime does inside a live Google Ads account to understand how autonomous bid management and budget reallocation actually work in practice.
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Frequently Asked Questions
How do I find my company registration number if I have lost my certificate?
Search the Companies House register at find-and-update.company-information.service.gov.uk using your company name. The registration number appears immediately in the search results without needing to log in or pay anything. If your company name has changed since incorporation, search under the original registered name.
What is the difference between a company registration number and a VAT number?
A company registration number is issued by Companies House when a company incorporates and identifies the legal entity on the UK register. A VAT number is issued separately by HMRC and only applies to businesses that are VAT-registered. They are different numbers serving different purposes, and not every company with a CRN will have a VAT number.
How do I find a company registration number for a business I want to verify?
Use the free Companies House register and search by company name, registered address, or director name. The CRN appears in the search results alongside the company's status, registered address, and filing history. This works for any UK-incorporated entity, whether currently active or dissolved.
Why do some company registration numbers have letters at the start?
The prefix indicates where and how the company was incorporated. SC indicates Scotland, NI indicates Northern Ireland, OC indicates a limited liability partnership, and LP indicates a limited partnership. English and Welsh private limited companies have no letter prefix — just eight digits, sometimes with leading zeros.
For more on this, see our guide: Companies House Email Address: What SMEs Need to Know.
For more on this, see our guide: Companies House Contact Number: What SMEs Need.
For more on this, see our guide: Companies House Contact Number: What SMEs Need.
Should I display my company registration number on my website?
Yes — for limited companies, it is a legal requirement under the Companies Act 2006 to display the company registration number on your website, emails, and letterhead. The registered office address must also be included. Sole traders and partnerships are not subject to this requirement as they do not have a CRN.