How to convert 21 stones to kilograms?

To convert 21 stones to kg, multiply 21 by 6.35029 (rounded to 5 digits). That makes 21 stones equal to 133.35616 kg.

21 stones to kg formula:
kg = number of stones * 6.35029
kg = 21 * 6.35029
kg = 133.35616

What is a Stone?

A stone is a unit of mass in the imperial system. The symbol of stone is st. One stone is equal to 14 pounds or approximately 6.35 kilograms. The stone continues in customary use in the United Kingdom and Ireland for measuring body weight.

The stone is not an SI unit, but it is still widely used. It stone is a relatively old unit of measurement, and its origins are unclear. The stone is thought to have originated in England in the Middle Ages. The stone was originally used to measure the weight of wool, but it soon came to be used to measure the weight of other goods, such as grain and livestock.

What is a Kilogram?

A kilogram is a unit of mass in the International System of Units (SI). The symbol of kilogram is kg. It is the base unit of mass, and is defined as being equal to the mass of the International Prototype Kilogram (IPK), a cylinder of platinum-iridium alloy kept at the International Bureau of Weights and Measures (BIPM) in Sèvres, France.

The kilogram is the most widely used unit of mass in the world. It is used to measure the mass of objects in science, engineering, commerce, and everyday life. Historically, the kilogram was defined as the mass of a liter of water at its freezing point, but this definition proved to be imprecise and led to inconsistencies.