The kilogram (abbreviation and symbol: kg) is the unit of mass in the metric system (SI, International System of Units). Kilogram is the base unit of mass in the metric system. 1 kilogram (kg) = 35.2739619 ounces (oz) = 1000 grams (g) = 1000000 milligrams (mg) = 2.20462262 pounds (lbs) = 0.157473044 stones (st).