What is the difference between ISO 9000, ISO 9001, ISO 9002, ISO 9003, and ISO 9004?

ISO 9000 indicates the overall series of the Quality Management System standards. ISO 9001 is the number of the actual standard to which a company achieves certification. Both terms are often used synonymously to refer to the certification. The year of the current revision of the standard appears in the title, such as ISO 9001.

Prior to the 2000 revision of the ISO standard, there were also ISO 9002 for companies who didn’t design any products, and ISO 9003 for companies who just did distribution. ISO 9002 and 9003 have been discontinued. Now, there is just the one standard, and if certain sections don’t apply, organizations can take an “exclusion” for those sections. ISO 9004 is a guidance document that helps explain the requirements of the 9001 standard. ISO 9000 itself is also a supporting document related to fundamentals and vocabulary.