Companies House number lookup – the complete guide

A Companies House number is the single most useful identifier a UK business has. Names can be duplicated, rebranded or quietly dropped. Addresses move. Trading styles are invented. The company number is permanent – once assigned on incorporation, it stays with the entity for its entire life, through every name change, share issue, rebrand and restructure.

This guide covers how to find a company's number when you don't have it, what the number actually encodes, and the verification you should always run once you do.

What a Companies House number is

Every entity on the UK Companies House register – limited companies, LLPs, limited partnerships, overseas entities registering a UK establishment – gets a unique number on incorporation. The number is public, permanent and printable. It identifies the legal person that owns contracts, assets and liabilities, regardless of what the company calls itself this week.

The format tells you something about where the company is registered:

• 00000000 – 09999999 – England and Wales, incorporated before roughly 2017
• 10000000 upwards – England and Wales, more recent incorporations
• SC + 6 digits – Scotland
• NI + 6 digits – Northern Ireland
• OC + 6 digits – Limited Liability Partnership (LLP), England and Wales
• SO + 6 digits – Scottish LLP
• NC + 6 digits – Northern Ireland LLP
• LP + 6 digits – Limited Partnership
• FC + 6 digits – Overseas company with a UK establishment
• OE + 6 digits – Overseas entity registered under the 2022 Act

A "company number" that doesn't match any of these formats is not a Companies House number – it may be a VAT number (GB + 9 digits), a charity number, or simply fabricated.

Five ways to find a company number

1. Ask

The fastest route, and the one most people overlook. Every legitimate UK company is required by s.82 of the Companies Act 2006 to display its registered name, registration number and country of registration on all business letters, order forms, websites and email footers. If you've received any paperwork from them, it's almost certainly already there.

Check in this order:

• The bottom of their website (usually in a faint row under the footer)
• The footer of their emails, especially automated ones like invoices or receipts
• The company details section of any contract or quote
• Their VAT invoice – the company number must appear on compliant invoices

2. Search Companies House by name

Go to the Companies House free company information service and type the trading name. Common gotchas:

• "Ltd" vs "Limited" – the register is relaxed about either, but returns both as separate entries
• Trading names – a company can trade under any name, but the register only knows its registered name
• Common names – "ACME Services Ltd" returns dozens; narrow by the registered office or incorporation year

When there are multiple matches, match against the registered office postcode you have on file before committing to one.

3. Search on B2Verify

B2Verify lets you search the full Companies House directory by name, company number or director name in a single box. The difference versus the official service is that each result shows a Trust Score, status and headline risk signals alongside – so you're not just finding the number, you're also confirming you've got the right entity without opening four tabs.

4. Cross-reference VAT number

If you only have a UK VAT number (GB123456789), cross-reference via the HMRC VAT checker. The VAT checker returns the registered company name; then search that name on Companies House to resolve to the number.

Note: a VAT number does not imply the company is limited – sole traders have VAT numbers too. If the entity isn't on Companies House, there's no Companies House number to find.

5. Check the PSC register

If you know who a Person with Significant Control is (an owner with 25%+ voting rights), you can look them up via Companies House officer search. The PSC's appointments page lists every company they control, with numbers.

Once you have the number, run these checks

Getting the company number is the easy part. What actually protects you is what you do with it.

Status

The overview page tells you whether the company is Active, Active – Proposal to Strike Off, Dormant, Liquidation, or Dissolved. Only "Active" – with no strike-off proposal – is safe for normal trading.

Confirmation statement

Look at the most recent CS01 filing. If it was filed within the last 14 months, the company is up to date. If it's overdue, the company may be within weeks of strike-off.

Accounts

The filing history lists every accounts submission (type AA). Read the most recent set – even abbreviated accounts tell you whether the company has any assets, any trading history and whether its net position is positive.

Directors

The "People" tab lists current and resigned officers. A director who controls a dozen other companies, most of them dissolved, is a pattern worth looking into before you commit to a contract.

People with significant control

The PSC register shows who actually owns and controls the company. If the PSC is an offshore entity with no ultimate beneficial owner recorded, you are looking at deliberately obscured ownership – which may or may not be a problem, but is always worth raising.

All five of these checks are visible on a company's B2Verify page in a single scroll. The annotated walkthrough of a sample report shows where each one lives on the page. The underlying data is the same Companies House data that's free to access – B2Verify's role is to put it in one place with a risk rating, and to alert you the moment anything changes.

Common mistakes

Confusing company number with VAT number. The company number is issued by Companies House and is permanent. The VAT number is issued by HMRC, only when the company registers for VAT, and ends when the company deregisters. They are different identifiers for different purposes.

Assuming a Companies House number means "this is a real trading business." It only means a company exists on the register. Dormant companies, non-trading companies and companies in proposal-to-strike-off all have perfectly valid numbers. Always pair the number with a status check.

Not matching the name. The name on a quote or invoice must match the registered name on Companies House. A company can have trading names, but the legal name on contracts and invoices must be the registered name. Mismatches are a common impersonation pattern – the impersonator picks a company number that looks plausible, but the name doesn't match.

Using the number as the only check. The number confirms identity. It tells you nothing about whether the company pays its suppliers, has the cash to deliver, or is run by a disqualified director. Always pair with filing history and people-level checks.

When the number doesn't exist

If Companies House returns no result for the number you were given, one of three things is true:

1. It's been entered wrong. Leading zeros matter – 00012345 is valid, 12345 is not (although the service will often find it anyway). Double-check the source.
2. The entity is not a UK limited company. Sole traders, partnerships without LP structure, and unincorporated associations don't have Companies House numbers.
3. The number is fabricated. If the person quoting you a number can't produce a matching Companies House record, treat it as warrants written verification before payment until proven otherwise.

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Looking up a specific company? Start with B2Verify – you'll get the Companies House record, filing history, director network and a Trust Score in one view, free.