In the UK and Ireland people describe body weight in stones and pounds — “eleven stone four” — while doctors, gyms, fitness apps and every other country use kilograms. This converter takes the two-part figure exactly as it is spoken and returns kilograms to two decimals, along with total pounds and the equivalent in decimal stone.
How to use the stone to kg converter
- Enter the whole stones in Stone (st).
- Enter the extra pounds in Pounds (lb), normally 0 to 13. Leave it blank for a whole number of stone.
- Read the result in kilograms. If you type 14 lb or more, the converter tidies it into stones and pounds for you.
- The chart below lists 6 to 25 stone in half-stone steps.
Stone to kilograms formula
A stone is 14 avoirdupois pounds, so the cleanest route is via pounds:
For whole stones you can use the stone factor directly:
Worked example: 11 stone 4 pounds
Step 1. Total pounds: 11 × 14 + 4 = 158 lb.
Step 2. 158 × 0.45359237 = 71.6676 kg, which rounds to 71.67 kg.
Step 3. As decimal stone: 158 ÷ 14 = 11.2857 st.
For a weight-loss goal, the same arithmetic works on the difference. Losing 2 stone is 28 lb, or 12.70 kg.
Body weights in stone and kilograms
| Stone and pounds | Kilograms | Pounds |
|---|---|---|
| 8 st 0 lb | 50.80 | 112 |
| 9 st 7 lb | 60.33 | 133 |
| 10 st 0 lb | 63.50 | 140 |
| 12 st 0 lb | 76.20 | 168 |
| 14 st 0 lb | 88.90 | 196 |
| 15 st 10 lb | 99.79 | 220 |
| 16 st 0 lb | 101.60 | 224 |
A useful landmark: 15 st 10 lb is almost exactly 100 kg. The calculator’s chart fills in every half stone from 6 to 25.
Decimal stone vs stone and pounds
Spreadsheets and some apps store weight as decimal stone, which causes confusion because the fractional part is in fourteenths, not tenths or pounds:
| Decimal stone | Stone and pounds |
|---|---|
| 11.25 st | 11 st 3.5 lb |
| 11.5 st | 11 st 7 lb |
| 11.75 st | 11 st 10.5 lb |
Multiply the decimal part by 14 to get the pounds. It’s a common slip to read 11.5 st as “eleven stone five”.
Why 14 pounds?
The stone is an old English trade weight, and historically its size depended on what was being sold — wool, meat and other goods used different stones in different towns. The 14 lb stone became the standard in British law in the 19th century. It was dropped as a legal unit of trade by the Weights and Measures Act 1985, but it lives on as the everyday way to talk about body weight in Britain and Ireland, even though hospitals record kilograms.
Using the result in health calculations
BMI, calorie and medication formulas expect kilograms, so convert from stone first and keep two decimals. The BMI calculator and ideal weight calculator both take kilograms. To show a kilogram reading as stones and pounds, use kg to lbs, which includes a stone-and-pounds row.
Frequently asked questions
How many kilograms are in a stone?
One stone is exactly 6.35029318 kg. A stone is 14 pounds, and each pound is exactly 0.45359237 kg.
How many pounds are in a stone?
Fourteen. So 11 st 4 lb is 11 × 14 + 4 = 158 lb.
What is 10 stone in kg?
10 stone is 63.50 kg. Each additional stone adds about 6.35 kg, so 12 stone is 76.20 kg and 14 stone is 88.90 kg.
What does 11.5 stone mean?
Decimal stone is not stone and pounds. 11.5 st is 11 st 7 lb (half of 14 lb is 7), which is 73.03 kg — not 11 st 5 lb.
How do I convert kilograms back to stone?
Divide the kilograms by 6.35029318 for decimal stone, or divide by 0.45359237 to get pounds and then split by 14. For 70 kg: 154.32 lb, which is 11 st 0.3 lb.