To check a company name in the UK, use Companies House's free company name availability checker. It tells you whether your proposed name is the "same as" one already on the register, which would block registration. A clear result is not the whole answer, though. A name can still be challenged if it is "too like" an existing name (a direction to change can be made within 12 months of registration), if it uses a sensitive word without approval, or if it infringes someone's trade mark. A proper check covers all four.
Step 1: the Companies House availability search
Section 66 of the Companies Act 2006 prevents a company being registered with a name that is the same as another name in the registrar's index. The availability checker applies that test for you. "Same" is wider than identical. Under the rules Companies House applies, certain elements are disregarded when names are compared, including:
- Company type endings such as "Limited", "Ltd" and "PLC";
- Most punctuation, signs and symbols;
- "The" and "www" at the beginning of a name;
- Equivalent words and characters, so "and" and "&" are treated alike, as are "0" and "zero";
- Characters after the first 60 in a name.
So "The Green Kitchen Ltd" is the same as "Green Kitchen Limited". If the checker says your name is unavailable, you can only use it if your company is, or will be, in the same group as the existing company or LLP and that company or LLP gives written consent.
Step 2: is it "too like" another name?
A name that passes the "same as" test can still be too close to an existing one. It might differ by a few characters, or look and sound the same. If someone complains and Companies House agrees, the Secretary of State can direct the company to change its name. Under section 68 that direction must be given within twelve months of the company's registration by that name, and the company gets at least 28 days to comply. The checker does not test for this, so search the register yourself for close variants, including different spellings and plurals.
Separately, anyone with goodwill in a name can object to the Company Names Tribunal, part of the Intellectual Property Office. They can do this where a company's name is the same as theirs, or similar enough to mislead people into suggesting a connection. The company can defend itself by showing, for example, that the name was registered before the objector's activities began, that it was adopted in good faith, or that the objector's interests are not significantly affected. The first of those defences fails if the main purpose of registering the name was to extract money from the objector or to block them.
Step 3: sensitive words and prohibited names
Some words need permission before they can appear in a name. These are words suggesting national or international pre-eminence, a connection with government or a local authority, or a regulated activity. GOV.UK's list of sensitive words includes, for example, "Royal", "British" and "Charity". Each comes with its own approval route, such as a letter of non-objection from the relevant body or evidence that the company is pre-eminent in its field. Without the supporting evidence, Companies House will reject the application.
Certain names cannot be registered at all. Under the Companies Act 2006, the Secretary of State will refuse a name that:
- Would be an offence to use, or is offensive (s53);
- Is intended to facilitate fraud or another offence involving dishonesty or deception (s53A);
- Consists of or includes computer code (s57A);
- Gives a false impression of a connection with a foreign government or an international organisation of states (s56A).
The fraud, computer-code and foreign-government restrictions were added by the Economic Crime and Corporate Transparency Act 2023. They reflect Companies House's stronger role in policing what goes on the register.
Step 4: trade marks, domains and the practical test
Companies House does not check trade marks. A registered name gives you no right to trade under it if that would infringe someone else's mark. GOV.UK warns that a name too similar to another company's trade mark may have to be changed after a complaint. Search the UK Intellectual Property Office trade marks register before committing. For a business trading internationally, check the main overseas registers too. It is also sensible to check:
- Domain names and social handles, which are separate from company registration and may already be taken;
- Trading names in your sector, since an unregistered business with goodwill in a name can still bring a passing-off claim;
- The ending. A private limited company's name must end in "Limited" or "Ltd" (or "Cyfyngedig"/"Cyf" for a Welsh company). The ending does not make an otherwise identical name available.
Registering or changing the name
Once the name passes all four checks, it is registered as part of incorporation, which costs £100 online. The name does not have to match the brand you trade under. A company can trade under a different business name, as long as it still shows its registered name and number where the trading disclosure rules require it (see our guide to the company registration number).
An existing company can change its name, usually by special resolution of the shareholders. The change must be filed with Companies House. The standard online fee is £20 (£30 on paper), and a higher fee buys a same-day service. The new name is subject to exactly the same checks, and it takes effect only when Companies House registers it, not when the shareholders vote.
Acumon's company formation team checks names against the register, sensitive word rules and obvious conflicts before filing, and our company secretarial services handle name changes, resolutions and Companies House filings for existing companies.