Companies House
UK Company Register (Companies House Company Data)
Every live company on the UK register — 5.7 million of them — with registered name, address, company number, legal form, incorporation date, trading status and SIC industry codes. The free master list behind almost every B2B target list, customer check and market count.
At a glance
- Publisher
- Companies House
- Updates
- Updated monthly
- Cost
- Free — open data
- Last checked
- 2026-07-16
Professional & B2B servicesFinancial servicesInsuranceConstruction & tradesLogisticsBusiness & companies
What your business can use it for
- Sales prospectingBuild a target list filtered to your patch and your sectors — every limited company in the country, by industry code, area and legal form, at no cost.
- Customer & supplier checksCheck a customer or supplier is who they say they are before you extend credit: are they active, how long have they traded, have they changed name, do they have charges registered?
- Market analysisCount the companies in your sector and your area, and see how that has moved over successive monthly snapshots.
Works with data you already have
- Company numbers you hold for customers, suppliers or prospectsCompany numbersCompanyNumber is the 8-character CRN, zero-padded — the master key across every Companies House product
- A list of business names, with no company numbersBusiness namesCompanyName is stored uppercase with no original casing; matching by name alone is fuzzy and needs normalisation
- Your patch, territory or delivery-area postcodesPostcodesRegAddress.PostCode links to LSOA/LAD via the free ONS postcode lookup — but it is the registered office, not the trading site
How to get it
- Free Company Data Product — the whole register as one CSVBulk downloadNo account needed. A ~500 MB zip on the 1st of each month, or seven smaller part-files if bandwidth is tight.
- Companies House REST API — look companies up one at a timeAPIFree API key. Adds officers, filing history and people with significant control, which the bulk file does not carry. Limited to 600 requests per 5 minutes.
What's involved in using it
- It's one very large file of nearly 5.7 million companies, so while it's a single tidy download it's too big for a normal spreadsheet and needs a database or specialist tool to work with comfortably.
- The address shown is each company's official registered office — often an accountant's address — not where it actually trades, so it can mislead if you're mapping real business locations. Use business rates data if you need trading premises.
- Small formatting quirks — spaces stuck to some column names, dates in UK rather than international order, and company numbers that must keep their leading zeros — mean a bit of clean-up before it joins reliably to your own records.
The technical detail, for whoever sets it up (3)
- Live companies only. Dissolved companies drop off the register, so old company numbers may not resolve here.
- Trading names, brands and branches are not separate rows — only registered legal entities appear.
- SIC codes are self-declared at incorporation and rarely updated, so treat them as a rough sector signal rather than the truth.
Ask us about UK Company Register (Companies House Company Data)
Ask a factual question about UK Company Register (Companies House Company Data) — what it covers, how often it changes, whether it matches the records you keep — and we will answer, free. Or tell us what you are trying to work out, and we will tell you what it would take to get this data working next to the numbers you already have.