Stone to Kilograms

Body weight in the UK is usually given as stone and pounds, such as 12 st 4 lb. The converter above takes decimal stone, so turn the pounds into a fraction of a stone first: 4 lb is 4/14, about 0.286 st, which makes 12.286 st and about 78.02 kg. Converting through pounds gives the same result: 12 × 14 + 4 = 172 lb, times 0.45359237.

Fitness apps and doctors' forms often ask for kilograms. Entering the converted figure keeps BMI and dosing calculations correct, since those formulas expect metric input.

Scales sold in the UK usually switch between stone, pounds and kilograms with a button. If yours does, switch it to kilograms rather than converting, since the scale works internally in one unit and only changes the display.

The stone has been used in Britain since the Middle Ages, when its weight varied by trade and by town: a stone of wool was not the same as a stone of meat. The value of 14 pounds became standard over time and is fixed in law, with the pound defined in metric terms. The UK Weights and Measures Act 1985, Schedule 1 still lists the stone, though only for supplementary use in trade.

Weight in pounds rather than stone? Lbs to kg converts it directly, and the kg to lbs converter goes the other way.