Conversions
Stones to Pounds Converter
Convert UK stones to pounds and kilograms, both directions. Handles combined stone-and-pound body weight like 11 st 4 lb plus decimal pounds and kg.
Stones / Pounds / Kilograms Converter
71.7 kg equals
11 st 4.07 lb
Also 158.07 lb
Stones and pounds
11 st 4.07 lb
Total pounds
158.07 lb
Kilograms
71.70 kg
Stones (decimal)
11.2907 st
Formula: 1 stone = 14 pounds = 6.35029 kg. A stone has been fixed at 14 pounds since the UK 1835 Weights and Measures Act, and a pound is exactly 0.45359237 kg by the 1959 international agreement.
Frequently Asked Questions about the Stones to Pounds Converter
What is the history of the stone as a weight unit?
The stone goes back to Anglo-Saxon and medieval European trade, where merchants used literal stones of standardized weight at market scales. Local stones varied wildly by region and by commodity (wool, cheese, meat, hemp), with values from about 5 to 24 pounds. The UK 1835 Weights and Measures Act finally fixed the stone at exactly 14 pounds for all goods, replacing the patchwork of local definitions.
Where is the stone still used today?
Stones are still the default unit for personal body weight in the UK and Ireland, both in everyday conversation and in clinical contexts. NHS forms, GP scales, and gym equipment commonly read in stones and pounds. The US uses pounds only for body weight (never stones), and the rest of the world uses kilograms. Stone has been retired for trade and commerce in the UK since 1985.
Why is one stone exactly 14 pounds?
The 14 pound stone is the legacy of dozens of older regional stones that gradually converged. Wool stones, cheese stones, meat stones, and butcher's stones each had different values, but the wool stone of 14 pounds dominated long-distance trade in late medieval England. The 1835 act simply made that figure the only legal stone, and 14 has stayed the definition ever since.
How many kilograms in a stone?
One stone equals exactly 6.35029318 kg, derived from 14 pounds times the international pound (0.45359237 kg). For mental math, treat a stone as about 6.35 kg. So 10 stones is about 63.5 kg, and 12 stones is about 76.2 kg.
How do I read a body weight written as 11 st 4 lb?
Stone-and-pound notation lists the whole stones first, then the leftover pounds (always under 14). 11 st 4 lb means 11 times 14 plus 4 equals 158 pounds, which is 71.7 kg. The converter accepts that combined form directly, or you can enter pounds or kilograms and read back the equivalent stones-and-pounds.