A gramme is a fraction of an ounce. Each avoirdupois ounce weighs about 28.35 grammes, while a troy ounce weighs around 31.10 grammes. Most nations use the gramme as their primary unit of measurement, which is equal to 1/1000 kilogramme.
Avoirdupois ounces are typically used. These are a component of the American system that is widely used. Troy ounces are a unit of measurement that are often only used in the commodities market to quantify precious metals. The only significant market that still recognises the ounce as an official unit of measurement is the United States.