stone
Massexact by definition
The stone is exactly 14 avoirdupois pounds, which is exactly 6.35029318 kilograms. The factor is exact because the pound is exact. It survives in British and Irish everyday use for body weight and almost nowhere else.
Watch out: British body weight is stated in a mixed form, such as "11 stone 4", meaning 11 stone plus 4 pounds, which is 158 lb or 71.7 kg. The stone is not used in the United States, where the same weight is simply 158 pounds, and it is not used in Canada or Australia.
| 1 st | 6.3502932 kg |
Stones of varying size were used across medieval European trade as standard weights for wool, wax and other commodities, ranging from about 5 to 40 pounds depending on the good and the town. English statute law progressively narrowed the wool stone to 14 pounds, and that value is the one that survived.