ISO 9000 is actually an entire series of standards which includes the ISO 9000 standard, the well-known ISO 9001 standard, and the less-known ISO 9004 standard.
The ISO 9000 Standard
This standard is a supplemental document that defines the vocabulary used in ISO 9001 and ISO 9004. The actual ISO 9000 standard is relatively unknown and most people who say “ISO 9000” actually mean the ISO 9001 standard.
The ISO 9001 Standard
The ISO 9001 standard is the core component of the ISO 9000 standards series: it contains the requirements for a company's quality management system (QMS); these are the requirements against which a company can get certified and receive the prestigious ISO 9001 certification.
The ISO 9004 Standard
ISO 9004 contains optional guidelines to extend the benefits of ISO 9001 to a wider range of interested parties including society in general. ISO 9004 is little known and rarely used, probably because one cannot achieve certification against ISO 9004.
The ISO 9001 standard is a set of requirements that directs companies in the implementation of a quality management system (QMS).
The ISO 9001 standard is probably the best known international standard ever; it is implemented by well over one million companies and other organizations in over 175 countries. ISO 9001 addresses “quality management”. This means what the organization does to fulfill:
their customers' requirements, plus
any applicable regulatory requirements,
while aiming to
enhance customer satisfaction, and
achieve continual improvement of its performance.
ISO 9001 certification is the prestigious stamp of approval of a company's ISO 9001 quality management system.
An ISO 9001 certification (or accreditation) indicates that a company has implemented the ISO 9001 quality management system, follows all its requirements, and had a certification body audit and certify that the company is operating according to ISO 9001 requirements. In order for the ISO 9001 certification to have validity, the certificate needs to be issued by an independent and accredited registrar and bear not only the logo of the ISO 9001 registrar but also the logo of the accreditation body. There are many well-known accreditation boards including ANAB (of the USA), UKAS (of the UK), and JAS-ANZ (of Australia and New Zealand), to name just a few.
A word of caution...
Beware of ISO 9001 certificates that are issued by unethical companies that lack accreditation. There are some consultants and providers of templates that “guarantee” ISO 9001 certification and then provide an “ISO 9001 certificate” that is not backed up by an accreditation board. Displaying such a “certificate” will likely backfire and portray its bearer as dishonest.
The ISO 9001 certification has many names: ISO 9001 registration, ISO 9001 accreditation, as well as - more precisely - ISO 9001:2015 certification, ISO 9001:2015 registration, and ISO 9001:2015 accreditation (2015 indicates the revision of the standard). Some people would even simply call it ISO 9000 certification. For more information on the differences, see also below.
Most companies realize significant benefits by following the ISO 9001 requirements and holding an ISO 9001 certification.
The benefits of implementing an ISO 9001 quality management system and achieving certification can be divided into three groups:
Many people use these terms interchangeably when simply referring to the ISO 9001 standard.
Prior to December 2000, there used to be an ISO 9001, an ISO 9002 and an ISO 9003 standard against one could get certified; avoiding to consider the technical differences between them, people would just simply refer to each as ISO 9000 because ISO 9001, ISO 9002 and ISO 9003 were all part of the ISO 9000 series of standards. ISO 9002 and ISO 9003 have long been discontinued but many people continue to use the name of the series of standards - ISO 9000 - when referring to the famous ISO 9001 standard.
The International Organization for Standardization (ISO) revises the ISO 9001 standard every 6-8 years. To differentiate between the different revisions, the year of the revision is frequently added to the number of the standard. The current year 2015 revision of ISO 9001 is, therefore, called ISO 9001:2015. ISO 9001:2015 was published in September 2015 and supersedes the ISO 9001:2008 standard, which is gradually being phased out during a 3-year period until September 2018.
ISO 9002 and ISO 9003 no longer exist.
ISO 9001 is the famous quality management standard against which a company can achieve certification.
ISO 9000 is strictly speaking the ISO 9000 family of standards but it is often used when actually referring to its most famous member: ISO 9001.
ISO 9001:2015 indicates the current year 2015 version of the ISO 9001 standard (replacing ISO 9001:2008).
Most people who are mentioning ISO 9000 or ISO 9001 are referring to ISO 9001:2015.