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Its purpose is to promote the use and understanding of the International System of Units (SI), commonly known as the metric system.


The seven-segment SI wheel graphics used throughout this website are courtesy of the Bureau International des Poids et Mesures (BIPM).

The SI Brochure, published by BIPM, is the authoritative reference for all matters relating to the International System of Units (SI). Extracts from the SI Brochure have been reproduced on this website, under the terms of the Creative Commons Attribution 4.0 International License.

The latest edition of the SI Brochure can be found at the following link: