Picking a name feels like the fun part of starting a business — but it comes with more rules than most people expect, and they’re different depending on whether you’re a sole trader or a limited company. Getting this right at the start avoids a rebrand down the line.
Sole trader naming rules
As a sole trader, you can trade under your own name, or choose a separate trading name — there’s no registration required for the name itself. But there are restrictions on what you can use:
- It can’t include “Limited,” “Ltd,” “LLP,” “plc,” or similar, since these imply a company structure you don’t have
- It can’t be offensive
- It can’t suggest a connection with government or local authorities without permission
- It can’t be identical or misleadingly similar to an existing trademark — this is the one that catches people out, since there’s no registration check to stop you
- The name must be unique — Companies House will reject anything identical or too similar to an existing registered company
- It must end in “Limited” or “Ltd” (or the Welsh equivalents), unless you qualify for an exemption
- Certain words are restricted or require permission to use — anything implying a connection to government, royalty, or certain professions (like “Chartered” or “Institute”) needs justification
- It can’t be offensive or contain sensitive words without approval
- Searching the UK Intellectual Property Office’s trademark register for anything similar in your sector
- Checking domain name availability if you plan to trade online
- Doing a general web search to see whether the name is already in use, even informally
Whatever name you trade under, your own legal name must still appear on official documents like invoices and letterheads, alongside the trading name.
Example: A sole trader trading as “Riverside Joinery” would still need to show their own name — e.g. “Riverside Joinery, trading name of J. Smith” — on invoices.
Limited company naming rules
Company names go through a formal check at Companies House, which is stricter:
Companies House provides a name-checking tool as part of registration, so you’ll know immediately if a name is available.
Example: If “Riverside Joinery Ltd” is already registered, “Riverside Joinery Limited” or “Riverside Joinery (UK) Ltd” would likely still be rejected as too similar — Companies House looks past small variations like punctuation, “the,” or company suffixes.
Trademark basics
This is the area that trips up businesses of both structures. Being able to register a company name, or trade freely as a sole trader, does not mean the name is free of trademark conflicts.
Companies House and HMRC don’t check trademark registers — they check their own name lists. Someone could have a UK trademark on a name that’s still “available” to register as a company or use as a sole trader. If that happens and you start trading, the trademark holder can potentially force you to stop using the name and rebrand, sometimes after you’ve already invested in signage, marketing, and reputation under it.
Before settling on a name, it’s worth:
Example (sole trader): A freelance baker choosing a distinctive name for social media and word-of-mouth business faces lower trademark risk than a business that will spend heavily on branding — but it’s still worth a basic check before printing packaging.
Example (limited company): A company planning a franchise model or wider expansion has much more at stake in a name dispute, since a forced rebrand later is far more expensive when there are multiple locations or franchisees to update.
Registering a trademark of your own
Neither sole trader trading names nor limited company registration give you trademark protection automatically — they simply let you use a name, not exclusively own it. If protecting the name matters to your business, registering a trademark with the UK Intellectual Property Office is a separate, deliberate step, and one worth taking once you’re confident the name is here to stay.
The short version
| Sole Trader | Limited Company | |
|---|---|---|
| Name registration | None required | Registered with Companies House |
| Uniqueness check | No formal check | Checked against existing company names |
| Can imply “Ltd” status | No | Yes, must include it |
| Trademark protection | Not automatic | Not automatic |
A name that clears Companies House or causes no issue as a sole trader isn’t automatically safe from a trademark claim — that’s a separate check worth doing before you commit.