Fundamental units are the units of the fundamental physical quantities in SI system which are not formed fro other units. There are a total of seven fundamental units such as meter, kilogram, ampere, and second. Derived units are those units that are used for derived quantities. Examples of derived units are meter per second (distance), mole per cubic meter (amount of substance concentration) and specific volume (cubic meter per kilogram). Total of 21 derived SI units are present.