Signed by seventeen countries at Paris: the treaty that created the International Bureau of Weights and Measures

Background

The Convention to assure the international unification and improvement of the metric system, commonly known as the Metre Convention, was signed on 20 May 1875 and amended in 1921.
It is an international treaty whose purpose was the creation of an international organization called the BIPM.
The treaty was signed in Paris by seventeen countries, and the day is now celebrated around the globe as World Metrology Day.
The bodies that the treaty established are the General Conference on Weights and Measures (CGPM), the International Committee for Weights and Measures (CIPM) and the International Bureau of Weights and Measures (BIPM).
The BIPM is based at the Pavillon de Breteuil at Sèvres in France.
The treaty is one of the efforts made by countries in the second half of the nineteenth century to establish new forms of intergovernmental cooperation, alongside the International Telecommunications Union and the Universal Postal Union.
The 28th meeting of the CGPM was held from 13 to 15 October 2026 and adopted resolutions on universal adherence to the Metre Convention and on the future definition of the second.