In 1389 in England a stone of wool was defined as weighing fourteen pounds, and although a stone of other materials could weigh significantly more or less (in pounds), the stone in general usage became accepted as weighing equal to 14 lbs. The actual unit of the stone was commonly used as a measure of weight for trade purposes across Europe until the 19th century when most countries adopted the metric system, however, the actual weight of the stone varied from country to country, region to region, and even depending on what was being weighed or traded.

The name ‘stone’ derives from the practice of using stones as weights, a common practice worldwide for two millennia or more. By turn, this makes a stone equivalent to 6.35029kg. Although sanctioned by the EU for use as a supplementary unit it is essentially obsolete outside the UK and Ireland.Ī stone is a unit of weight equal to 14 pounds averdupois (or international lbs). The stone is a unit of weight in the imperial system used informally in the UK and Ireland, almost exclusively as a measure of body weight. The stone has not been officially recognised as a unit of weight in the UK since 1985. The stone is now used almost exclusively in the UK and Ireland, as a popular – if informal – way of expressing a person’s weight.12 st 6 lbs) instead of purely in pounds as would be the case in the United States (174 lbs). A British or Irish person will commonly express their weight in stone and pounds (eg.The stone is still habitually used to express human bodyweight in some sports in the UK and Ireland, such as boxing and wrestling.

The stone is also used in horse racing to describe the weight that a horse has to carry (not necessarily just the jockey, this weight can also include penalties and suchlike).

Conversion kgs to stones