How to use Companies House data for B2B lead generation.

If you sell to other businesses in the UK, your future customers are almost certainly already listed somewhere you can search for free. Companies House, the government's registrar of companies, holds public records for millions of UK companies. Used well, it's one of the best starting points for a B2B prospect list, because it's official, it's current and it covers every limited company, not just the ones that pay to appear in a directory.

This guide explains what the register contains, how to get at the data, how to narrow it down to a useful list and what you'll still need to find elsewhere.

What the Companies House register contains

Each company on the register has a public record. The details that matter most for prospecting are:

• Company name and number. The number is the company's unique identifier, which is useful for avoiding duplicates when two businesses have similar names.
• Company status. Whether the company is active, dissolved, in liquidation and so on. You only want active companies.
• Registered office address. The official address for legal post. This is often, but not always, where the business trades from.
• Incorporation date. When the company was formed, which tells you how long it has been trading.
• Nature of business (SIC codes). Up to four Standard Industrial Classification codes describing what the company does. See our guide to using SIC codes for prospecting.
• Officers. The company's current and past directors and secretaries, with names and appointment dates. These are the people who can usually say yes to a purchase.
• Filing history, including accounts. The accounts a company files, and the type of accounts it files, give a rough sense of its size.

You can look any company up for free using the Find and update company information service.

How to get the data

There are three practical ways in, depending on how many companies you want to look at.

The free online search

The Companies House search is ideal for checking individual businesses: confirming a company is active, seeing who its directors are or reading its latest accounts. It's not built for producing lists of hundreds of companies at once.

The public data API

Companies House offers a free public data API. You register for a key, then your software can search companies, read company profiles and list officers. It's rate limited, so it suits tools that look companies up as they need them rather than downloading everything at once.

Bulk data products

Companies House also publishes free downloadable snapshots of basic company data. These are useful if you want to filter the whole register yourself in a spreadsheet or database. Expect large files and some data cleaning before they're useful.

Building a target list from the register

The register lists millions of companies, so the real work is narrowing it down. Start from a clear picture of your ideal customer, then translate it into filters.

1. Keep only active companies. Remove anything dissolved, dormant or in insolvency proceedings.
2. Filter by industry using SIC codes. Pick the codes that match the businesses you serve, such as plumbing and heating installers or architectural practices.
3. Filter by location. Use the registered office postcode to keep companies within a radius of you, or within the regions you cover.
4. Filter by age. Use the incorporation date to skip businesses that are too new to buy. Very young companies often don't yet have budgets or established suppliers to replace.
5. Filter by size. The type of accounts a company files (for example micro-entity or small company accounts) gives a rough signal of size, which helps you match businesses to what you sell.
6. Remove duplicates and groups. Several companies can share directors, addresses or a website. Decide whether you want to contact each company, or each group once.

What Companies House won't tell you

The register is a starting point, not a finished prospect list. Know its gaps before you rely on it.

• No email addresses or phone numbers. Companies House doesn't publish contact details for directors. You'll need to find the company's website and the contact details published there.
• The registered office isn't always the trading address. Many companies use their accountant's or a formation agent's address. Distances calculated from a registered office can be misleading.
• Not every business is on it. Sole traders and ordinary partnerships aren't registered at Companies House, so the register won't show them. Limited liability partnerships are registered.
• SIC codes are self-chosen. Companies pick their own codes when they register, and many never update them. Some codes are broad catch-alls.
• Directors aren't always the right contact. In a small firm the director usually is the decision-maker. In a larger one, a director may be a finance or group appointment rather than the person who buys what you sell.

Turning a list into conversations

A list of company names doesn't make sales. To turn it into conversations you need three more steps.

1. Find each company's website. Match the company to its site, checking the name, location and, ideally, the company number in the site footer.
2. Find the right person and a working address. Match the directors on the register to the contact details published on the website, and check the address can receive mail. Our guide to finding a company director's email address covers this in detail.
3. Write to them personally, a few at a time. Short, relevant emails to a named person get replies. Mass mailings get ignored or reported as spam. Make sure you follow the rules in our guide to cold email law in the UK.

Doing it by hand versus automating it

All of this can be done by hand with the free search, a spreadsheet and some patience. For a handful of companies a week, that's fine. The time adds up quickly, though: each company means a search, a website hunt, matching directors and checking an address before you've written a word.

Pucky automates that work. It starts from the official Companies House register, filters it by industry, area, age and size, finds each business's website, collects the contact details published there and matches them to the company's directors. See how it works on the UK company search page.

Frequently asked questions

Want to see a list built from the register for your own area? Book a demo and we'll run a live search with you.