SI base units

Prior to 2019, the concept of base units and derived units was used to define the SI. These categories, although no longer essential in the SI, are maintained in view of their convenience and widespread use.

The seven SI base units, are listed here:

Name	Symbol	Quantity
kilogram	kg	mass
metre	m	length
second	s	time
ampere	A	electric current
kelvin	K	thermodynamic temperature
mole	mol	amount of substance
candela	cd	luminous intensity

All other SI units can be derived either from these seven base units, or directly from the seven SI defining constants.