1  |  Standard International Units (S.I)

What is basic units

The SI base units are the standard units of measurement defined by the International System of Units (SI) for the seven base quantities of what is now known as the International System of Quantities: they are notably a basic set from which all other SI units can be derived. The units and their physical quantities are the second for time, the metre for measurement of length, the kilogram for mass, the ampere for electric current, the kelvin for temperature, the mole for amount of substance, and the candela for luminous intensity. 

History of S.I 

Born in 20 May 1875, following the signing of the Metre Convention, a treaty among 17 Member States (as of November 2018 there are now 59 members). 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). The BIPM is supervised by the International Committee for Weights and Measures