Convert lbs to stone
Pound-force
The pound of force or pound-force (symbol: lbf sometimes lb f ) is a unit of force used in some systems of measurement including English Engineering units and the Foot–pound–second system. Pound-force should not be confused with foot-pound, a unit of energy, or pound-foot, a unit of torque, that may be written as "lbf⋅ft"; nor should these be confused with pound-mass (symbol: lb), often simply called pound, which is a unit of mass.
Stone
A stone (symbol: st) is an English and imperial unit of mass. It is defined as 14 pounds or 6.35029318 kilograms.
The name "stone" derives from the use of stones for weights, a practice that dates back into antiquity. The Biblical law against the carrying of "diverse weights, a large and a small" is more literally translated as "you shall not carry a stone and a stone (בן ואבן), a large and a small". There was no standardised "stone" in the ancient Jewish world, but in Roman times stone weights were crafted to multiples of the Roman pound. Such weights varied in quality: the Yale Medical Library holds 10 and 50-pound examples of polished serpentine, while a 40-pound example at the Eschborn Museum is made of sandstone.