During the Companies House registration process, new limited company directors are asked to select a Standard Industrial Classification code — commonly referred to as an SIC code. Many founders encounter this for the first time at the point of registration and are uncertain what it means, which code best describes their business, or whether getting it wrong causes problems later.
A Standard Industrial Classification (SIC) code is a reference code used by Companies House and government agencies to categorise businesses by the type of economic activity they carry out. Every limited company must provide at least one SIC code on registration. The code does not restrict what your business can legally do — it is used primarily for statistical and administrative purposes. If your business spans more than one type of activity, you can register multiple SIC codes to reflect that range.
Choosing the most accurate SIC code for your primary activity is good practice, as it can affect how your company appears in business data registers used by potential clients, lenders, and credit agencies. Our guide to registering a limited company walks through the registration process step by step, including how to select and verify your SIC code.