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Classification of Standard Industry

The North American Industry Classification System (NAICS) is used by business and government to classify business establishments according to type of economic activity (process of production) in Canada, Mexico and the United States. It has largely replaced the older Standard Industrial Classification (SIC) system; however, certain government departments and agencies, such as the U.S. Securities and Exchange Commission (SEC), still use the SIC codes. CSI helps you look those codes up.


This is a Ruby gem, so you'll need a little Ruby-fu to get it working. If you're not familiar with Ruby, there are CSV and TOML data sets available too that you can load into a spreadsheet, database or parse in your favorite programming language.

For Rubyists:

gem install csi

Or add this to your Gemfile:

gem 'csi', '~> 0.3.3'

For everyone else:

  • All NAICS and SIC codes, classifications, and correlations in TOML
  • NAICS codes and classifications in CSV
  • SIC codes and clasifications in CSV


You can look up 2-6 digits NAICS codes and 2-4 digit SIC codes. Please note: If you ever cast the String codes to Integers, you're gonna have a bad time. SIC code 011 is 011 as a String and 11 as an Integer. The more you know πŸ’«

naics_record = CSI::naics "928110"
# => <CSI::Record:0x007fb3c5fdbb98]
# => "National Security"

# => Military Armored Vehicle, Tank, and Tank Component Manufacturing

# => Colleges, Universities, and Professional Schools

# => Elementary and Secondary Schools

# => "Executive, Legislative, and General Government, except Finance"

You can also lookup correlating SIC codes for NAICS codes and vice-versa!

naics_record = CSI::naics("928110")
# => <CSI::Record:0x007fb3c5fdbb98]
# => "National Security"

# => "["9711"]"

correlating_sic_record = CSI::sic naics_record.correlations.first
# => <CSI::Record:0x007fd0bd9a4fd0>
# => "National Security"

NAICS & SIC Overview

Explaining NAICS and SIC is outside the scope of this README, but you'll find an extremely brief overview below. For more information you can check out the SIC page and NAICS page on Wikipeda.

Digit range NAICS Definition SIC Definition
1 - 2 Sector Major Group
1 - 3 Subsector Industry Group
1 - 4 Industry Group Industry
1 -5 NAICS Industry N/A
1 -6 National N/A

The larger the coode, the more specific the industry. Here's a NAICS example:

Code Name
48 Transportation & Warehousing (over arching industry and sub-sectors)
481 Air transportation
4812 Nonscheduled air transportation
48121 Nonscheduled air transportation
481212 Nonscheduled chartered freight air transportation

Data Sources

All codes and classifications obtained via, so you know it's legit.

Copyright (c) 2013 Lee Reilly. See for further details.

Many Bothans died to bring you this information.


😎 Look up NAICS (North American Industry Classification System) and SIC (Standard Industrial Classification) codes and how they correlate with one another







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