Kilogram and its multiples and subunits in the SI system.
The SI unit of measure for Mass is the kilogram. This may seem strange, since mass is not the same as weight. Mass becomes weight when acceleration due to gravity is applied.
In the metric system, you would use grams, kilograms, tonnes (1000 kg), and etc.
Other general units are tons, hundredweights, stones, pounds and ounces in the Imperial system.