What is the International System of Units?

The International System of Units, sometimes abbreviated as SI, is the measurement system officially adopted almost everywhere in the world. It consists of a set of seven base units that include second, meter, kilogram, ampere, kelvin, mole, and candela. These units allow an unlimited number of additional derived units, through which it is theoretically possible to measure everything in the universe.

The 7 base units

This list shows the 7 base units, from which all other units of measure are derived.

Dimension
Symbol
Quantity
Name
Unit
Symbol
Unit
Name
IElectric CurrentAAmpere
JLuminous IntensitycdCandela
LLengthmMetre
MMasskgKilogram
NAmount of SubstancemolMole
TTimesSecond
ΘThermodynamic TemperatureKKelvin