Convert Stone to Kilogram

One stone equals exactly 14 pounds, which equals 6.35029318 kilograms — a precise figure derived from the pound's definition of 0.45359237 kg. To convert stone to kilograms, multiply by 6.35029318. A person weighing 11 stone is 69.85 kg; a 14-stone person is 88.90 kg.

The stone is used almost exclusively for human body weight in the United Kingdom and Ireland, and occasionally in Australia and New Zealand among older generations. It has no official status in the metric SI system, and it is entirely absent from everyday American usage — which is pounds only. A British patient telling a US doctor they weigh '13 stone 8' needs a quick conversion: 13 × 14 + 8 = 190 lb = 86.18 kg.

The arithmetic requires two steps when stones and pounds are mixed. A weight of 10 stone 5 lb means (10 × 14) + 5 = 145 lb = 65.77 kg — you cannot simply convert stone and pounds separately and add the kg results without first combining into total pounds (or total stone). The intermediate step of summing in pounds first avoids the most common calculation error.

UK bathroom scales sold before metrication typically display in stone and pounds; digital scales sold now often display all three — stone/lb, kg and lb. NHS health records increasingly use kilograms for clinical consistency, so the conversion from the scale reading to the medical record is a step patients carry out themselves. Knowing that 1 stone = 6.350 kg makes the arithmetic straightforward for any weight in whole stones.