The International Bureau of Weights and Measures (French: Bureau international des poids et mesures) is an intergovernmental organisation that was established by the Metre Convention, through which member states act together on matters related to measurement science and measurement standards.

The organisation is commonly referred to by its French initialism, BIPM. The BIPM's secretariat and formal meetings are housed in the organisation's headquarters in Saint-Cloud, France.

The BIPM is supervised by the International Committee for Weights and Measures , a directorate of eighteen members that meet normally biannually, which is in turn overseen by the General Conference on Weights and Measures  that meets in Paris usually once every four years, consisting of delegates of the governments of the Member States and observers from the Associates of the CGPM.

The BIPM was created on 20 May 1875, following the signing of the Metre Convention, a treaty among 59 Member States (as of November 2018). It is based at the Pavillon de Breteuil in Saint-Cloud, France, a 4.35 ha (10.7-acre) site (originally 2.52 ha or 6.2 acres) granted to the Bureau by the French Government in 1876.

Since 1969 the site of the Pavillon de Breteuil is considered international territory and the BIPM has all the rights and privileges accorded to an intergovernmental organisation.The status was further clarified by the French decree No 70-820 of 9 September 1970.

The BIPM has the mandate to provide the basis for a single, coherent system of measurements throughout the world, traceable to the International System of Units (SI). This task takes many forms, from direct dissemination of units to coordination through international comparisons of national measurement standards (as in electricity and ionizing radiation).

The BIPM has an important role in maintaining accurate worldwide time of day. It combines, analyses, and averages the official atomic time standards of member nations around the world to create a single, official Coordinated Universal Time (UTC).

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According to en.wikipedia