Convert pounds to stones

Pound

Definition: A pound (symbol: lb) is a unit of mass used in the imperial and US customary systems of measurement. Since 1959, the international avoirdupois pound has been officially defined as exactly 0.45359237 kilograms.

History/origin: The pound originated from the Roman libra (hence the "lb" abbreviation), which was equivalent to 328.9 grams. Various definitions of the pound were used throughout Europe in the Middle Ages, differing from city to city and country to country.

The avoirdupois pound, which is the most commonly used pound today, was established in England during the 13th century and was used for weighing wool. The avoirdupois system introduced the concept of a 16-ounce pound, which eventually became the standard for most commodities.

Prior to the international agreement in 1959 that standardized the pound to exactly 0.45359237 kilograms, the pound was defined differently in various countries. The United States and countries of the Commonwealth of Nations agreed to this definition to ensure international consistency in trade and commerce.

Current use: The pound is primarily used in the United States and, to a varying extent, in other countries historically tied to the British Empire, such as the United Kingdom, where it remains in common use despite official adoption of the metric system. It's commonly used for personal weight, food measurements, and various commercial applications.

Stone

Definition: The stone (symbol: st) is a unit of mass primarily used in the United Kingdom and Ireland. It is defined as 14 pounds (approximately 6.35 kilograms).

History/origin: The stone originally varied in weight depending on the commodity being weighed. It was often used in trade, with different stones for products like wool, cheese, and meat.

The standardization of the stone to 14 pounds occurred in the 14th century, and it became particularly associated with measuring a person's body weight.

Current use: The stone is primarily used in the UK and Ireland for expressing human body weight. While other units like pounds and kilograms are also used, stone remains a common way for people to describe their weight.