The International System of Units - 9th edition (2019)
Bureau International des Poids et Mesures
Published in May 2019 - Revised in August 2025
Citation Bureau International des Poids et Mesures. (2025). Le Système international d'unités/The International System of Units [Brochure].
Abstract
The International System of Units (SI) has been used around the world as the preferred system of units, the basic language for science, technology, industry and trade since it was established in 1960 by a resolution at the 11th meeting of the Conférence Générale des Poids et Mesures (CGPM).
This brochure is published by the Bureau International des Poids et Mesures (BIPM) to promote and explain the SI.
French text English text
| Version | Publication date | Changes |
| 3.02 | August 2025 | Revision of the value of the dalton, update of the list of binary prefixes |
| 3.01 | August 2024 | Improvements to the descriptions of angle and quantities with the unit one |
| 2.01 | December 2022 | Introduction of the new SI prefixes adopted by the CGPM at its 27th meeting (November 2022) |
| 1.01 to 1.08 | May 2019 to September 2021 | Editorial changes |
 Creative Commons Attribution 4.0 International License |