Stone and pounds converter
Convert between stone and kilos either way, plus pounds only and decimal stone.
Your details
Switch to kg to convert the other way.
In kilograms
68.0 kg
10 st 10 lb
- Pounds only150 lb
- Stone as a decimal10.71 st
- Grams68,039 g
- BMIadd your height to see BMI and the healthy range in both units
One stone is 14 pounds, and one pound is exactly 0.45359237 kg, so a stone is about 6.35 kg.
The working
The sum
One stone is 14 pounds. One pound is exactly 0.45359237 kg, a figure fixed by international agreement in 1959. So:
- Stone to kg: (stone × 14 + pounds) × 0.4536
- Kg to stone: kg ÷ 6.35, then turn the decimal part into pounds by multiplying by 14
10 st 10 lb is 150 lb, and 150 × 0.45359237 = 68.0 kg.
Cheat sheet
Common weights
| Stone | Kilograms |
|---|---|
| 8 st | 50.8 kg |
| 9 st | 57.2 kg |
| 10 st | 63.5 kg |
| 11 st | 69.9 kg |
| 12 st | 76.2 kg |
| 13 st | 82.6 kg |
| 14 st | 88.9 kg |
| 15 st | 95.3 kg |
| 16 st | 101.6 kg |
Fun fact
Why stone?
A stone was originally an actual stone used on market scales, and its weight changed with the town and the goods: a stone of wool could be 14 lb while a stone of meat in London was 8 lb. The 14 lb stone became the standard in 1835. The UK is one of the last places that still weighs people in it.
Extras
BMI and change in both units
Add your height and the converter also gives your BMI and the NHS healthy weight range for that height, in stone and in kilos, so a GP letter and your scales agree. At 5 ft 7 in (1.702 m), 10 st 10 lb (68.0 kg) is a BMI of 68.0 ÷ 2.897 = 23.5, and the range is 53.6 to 72.1 kg (8 st 6 lb to 11 st 5 lb).
Add an earlier weight to see the change in kilos, pounds and as a percentage. If you have lost 5% or more without trying, that is worth mentioning to your GP.
Questions
Common questions
How many kg is 1 stone?
6.35 kg, to two decimal places. Exactly, it is 6.35029318 kg.
How do I convert kg to stone and pounds?
Divide by 6.35 to get stone. Take the whole number, then multiply what is left after the decimal point by 14 to get pounds.
Why does the NHS use kg?
Hospitals work in metric so medicine doses are safe and consistent. Most NHS tools, including ours, let you type stone and convert it for you.
Sources
- NHS: unintentional weight loss
- UK Weights and Measures Act 1985, schedule 1 (pound defined as 0.45359237 kg)
- NHS: BMI calculator for adults (stone or kg)
Last checked 21 October 2026. Spotted something wrong? Tell us and we will fix it.
If your weight is on your mind
Talk to your GP if your weight has changed a lot without trying, or if it is worrying you. If food or your body feels hard to think about, Beat has a free helpline on 0808 801 0677 (England, weekdays 3pm to 8pm).
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