Metric system

The metric system is a number of different systems of measurement with length based on the metre, mass on the gram, and volume on the litre.^[1] This system is used around the world. It was developed in France and first introduced there in 1795, 2 years after the execution of Louis XVI. The metric units are based on decimal groups (multiples of ten). At first the metric system was based on two quantities: length and weight. The basic units were called the metre and the gramme.

In 1866, the United States started to use the metric system, and is widely used except by the public.^[2] By 1875, many countries in Europe and in Latin America had changed to using the metric system. In 1875, seventeen countries signed the Metre Convention agreeing to share responsibility for defining and managing the metre and kilogram standards.^[a] The prototype^[b] copies of the metre and of the kilogram were called the "international prototype metre" and "international prototype kilogram". A new organization called the International Bureau of Weights and Measures (BIPM) was set up. The international prototype metre and kilogram were kept at the BIPM headquarters. In 1960, the rules for the metric system were revised. The revised system was called the "International System of Units" (which is often called "SI" for short). The definition of SI also included rules for writing SI quantities. These rules are the same for all countries. In the 1970s, many people in the United Kingdom and the rest of the Commonwealth started using the metric system in their places of work.

1. ↑ "Oxford Dictionaries". Archived from the original on 2015-11-30. Retrieved 2014-07-29.
2. ↑ "The Metric System in the U.S." 17 July 2020. Archived from the original on 6 July 2014. Retrieved 29 July 2014.