What this means
A company database normally starts with registered entities. That gives you a durable identifier, company status and basic filing context. It does not automatically tell you what the business sells, which brand it trades under or whether it is commercially relevant to your use case.
For market mapping, sales or supplier research, separate the legal entity from the trading business. One group can have several entities, one entity can have several brands, and a registered address may not be an operating location.
Main data sources
Companies House is the foundation source for UK limited companies and other companies covered by the Companies Act 2006. It provides company numbers, registered names, status, officers, filing history and related records.
Other sources can add context: charity registers, mutuals, regulator lists, public datasets, websites, procurement records, planning records, directories and commercial company databases.
Free sources
Free sources are strong for entity discovery and public record checks. Companies House is the natural starting point. Data.gov.uk, ONS, regulator publications and local authority datasets can support geographic, sector and policy context.
Free data often requires more work. You may need to normalise addresses, resolve duplicate names, map SIC codes, infer trading activity and add a manual review step.
Paid and commercial sources
Commercial company databases can add firmographics, contact data, group structures, industry tags, revenue estimates, employee estimates and export tools. They can be valuable when speed matters or when the dataset needs to feed a workflow.
The important question is not whether a vendor has many records. It is whether the provider has strong UK coverage for your segment, a clear sourcing model, acceptable licence terms and measurable match quality.
API options
Company data APIs help with lookup, enrichment, monitoring and entity resolution. Use the company number as the preferred identifier when available. Company names are useful but can change, collide or include punctuation variants.
For production use, log source, retrieval time and match confidence. Avoid silently overwriting internal records with an API response unless the matching rule is explicit.
Common use cases
Use cases include building company universes, cleaning CRM data, checking filing status, resolving company names, enriching supplier records, finding similar businesses and creating sector maps.
A research-grade company database should show how each company entered the list. A sales list may optimise for speed, but a diligence list should optimise for traceability.
Limitations
Companies House data is legal entity data. It may not include current websites, contacts, live headcount, customer type, buying intent or meaningful sector categories. SIC codes are useful, but often too broad or stale for precise segmentation.
A good UK company database makes these limits visible instead of hiding them behind a single confidence score.
Official sources
These links are starting points for source checks. Always confirm current terms, coverage, authentication and update frequency before relying on a dataset operationally.
FAQ
Where can I find a UK company database?
Companies House is the main public source for registered company records. Commercial providers can add enrichment, contacts, sector tags and workflow tooling.
Is UK company data free?
Some UK company data is freely available, especially core Companies House records. Commercially useful enriched data often requires paid tools or manual processing.
What is a company number?
A company number is the unique identifier assigned to a registered company. It is often more reliable than company name matching because names can change or collide.
What is the difference between registered and trading data?
Registered data describes the legal entity. Trading data describes how the business operates in the market, including brands, websites, locations, services and live activity signals.