The Bureau International des Poids et Mesures, the BIPM, was established by Article 1 of the
Convention du Mètre, on 20 May 1875, and is
charged with providing the basis for a single,
coherent system of measurements to be used
throughout the world. The decimal metric system,
dating from the time of the French Revolution,
was based on the metre and the kilogram. Under
the terms of the 1875 Convention, new international
prototypes of the metre and kilogram were
made and formally adopted by the first Conférence
Générale des Poids et Mesures (CGPM) in 1889.
Over time this system developed, so that it now
includes seven base units. In 1960 it was decided
at the 11th CGPM that it should be called the
Système International d’Unités, the SI (in English:
the International System of Units). The SI is not
static but evolves to match the world’s increasingly
demanding requirements for measurements
at all levels of precision and in all areas of
science, technology, and human endeavour. This
document is a summary of the SI Brochure, a
publication of the BIPM which is a statement of
the current status of the SI.
The seven base units of the SI, listed in Table 1,
provide the reference used to define all the measurement
units of the International System. As
science advances, and methods of measurement
are refined, their definitions have to be revised.
The more accurate the measurements, the greater
the care required in the realization of the units of
measurement
