The base unit for volume metric system is liter. 1 liter is the volume of fluid that occupies 1000 cubic centimeters.
Other volume metric system units include; milliliter, centiliter, deciliter, deciliter, hectoliter, kiloliter, etc
You can also convert volume units from Imperial or US customary units to metric system units and vice versa.
The conversion rules/factors vary widely. Follow the links below for specific conversion instructions from one unit to the other.