According to the United States Census Bureau, both the Standard Industrial Classification (SIC) and North American Industrial Classification System (NAICS) classify establishments by their primary type of activity. Companies generally determine their own codes based on descriptions provided in each system, and can thus be compared to other like companies. This structured information enables economic analysis on a local, national, and to some extent, international basis.
The SIC code system was replaced by the North American Industrial Classification System in 1997, although both are still in common use. SIC codes are primarily for manufacturing industries, while NAICS codes add service industries.
To find an NAICS code, visit the NAICS site of the United States Census Bureau.
To find an SIC code, visit the SIC site of the Occupational Safety and Health Administration Department at the United States Department of Labor.