Stone to Kilograms Converter (st to kg)
1 st = 6.35029318 kg exactly. Convert UK body weights in stone to kilograms, with stones-and-pounds splits and st to kg and kg to st charts.
Kilogram (kg) = Stone (st) × 6.35029318
Stone (st): A stone is 14 pounds, exactly 6.35029318 kilograms. In the UK and Ireland body weight is still commonly given in stone and pounds, such as 11 st 4 lb.
Kilogram (kg): The kilogram is the SI base unit of mass. Since 2019 it has been defined by fixing the value of the Planck constant, replacing the platinum-iridium prototype kept near Paris.
| Stone (st) | Kilogram (kg) |
|---|---|
| 1 | 6.35029318 |
| 5 | 31.7514659 |
| 10 | 63.5029318 |
| 25 | 158.7573295 |
| 50 | 317.514659 |
| 100 | 635.029318 |
In the UK and Ireland people still give their body weight in stones and pounds, such as 11 st 4 lb, while hospitals, gyms abroad and fitness apps set to metric want kilograms. One stone is 14 lb, and with the pound fixed at 0.45359237 kg that makes the stone exactly 6.35029318 kg.
The first chart covers adult weights in half-stone steps and adds a stones-and-pounds column, so 11.5 st reads as 11 st 7 lb. A reading in stones and pounds can be typed as a decimal: divide the loose pounds by 14 and add them to the stones.
How to use this tool
- Type a value in the Stone box to see it in kilograms, or type in the Kilogram box to convert the other way.
- Press ⇄ to swap the two units, or Load example for a typical value.
- Check the charts below for common values; for other units, open the Weight & Mass converter.
Formula
Kilogram (kg) = Stone (st) × 6.35029318
Stone (st) = Kilogram (kg) × 0.157473044418
Both factors come from exact definitions: 1 kilogram = 0.157473044418 stone and 1 stone = 6.35029318 kilograms (shown to 12 significant digits).
Example
Two conversions worked with the same factors the converter uses:
11.5 st × 6.35029318 ≈ 73.0284 kg
70 kg × 0.157473044418 ≈ 11.0231 st
Stone to Kilogram chart
Common values from stone to kilograms, rounded to four decimal places.
| Stone (st) | Kilogram (kg) | Stones and pounds |
|---|---|---|
| 1 | 6.3503 | 1 st 0.0 lb |
| 2 | 12.7006 | 2 st 0.0 lb |
| 4 | 25.4012 | 4 st 0.0 lb |
| 6 | 38.1018 | 6 st 0.0 lb |
| 7 | 44.4521 | 7 st 0.0 lb |
| 7.5 | 47.6272 | 7 st 7.0 lb |
| 8 | 50.8023 | 8 st 0.0 lb |
| 8.5 | 53.9775 | 8 st 7.0 lb |
| 9 | 57.1526 | 9 st 0.0 lb |
| 9.5 | 60.3278 | 9 st 7.0 lb |
| 10 | 63.5029 | 10 st 0.0 lb |
| 10.5 | 66.6781 | 10 st 7.0 lb |
| 11 | 69.8532 | 11 st 0.0 lb |
| 11.5 | 73.0284 | 11 st 7.0 lb |
| 12 | 76.2035 | 12 st 0.0 lb |
| 12.5 | 79.3787 | 12 st 7.0 lb |
| 13 | 82.5538 | 13 st 0.0 lb |
| 13.5 | 85.729 | 13 st 7.0 lb |
| 14 | 88.9041 | 14 st 0.0 lb |
| 15 | 95.2544 | 15 st 0.0 lb |
| 16 | 101.6047 | 16 st 0.0 lb |
| 17 | 107.955 | 17 st 0.0 lb |
| 18 | 114.3053 | 18 st 0.0 lb |
| 20 | 127.0059 | 20 st 0.0 lb |
| 25 | 158.7573 | 25 st 0.0 lb |
Kilogram to Stone chart
The reverse direction for values people often look up.
| Kilogram (kg) | Stone (st) |
|---|---|
| 40 | 6.2989 |
| 45 | 7.0863 |
| 50 | 7.8737 |
| 55 | 8.661 |
| 58 | 9.1334 |
| 63 | 9.9208 |
| 67 | 10.5507 |
| 72 | 11.3381 |
| 76 | 11.968 |
| 80 | 12.5978 |
| 86 | 13.5427 |
| 90 | 14.1726 |
| 95 | 14.9599 |
| 100 | 15.7473 |
| 110 | 17.322 |
| 120 | 18.8968 |
Traditional weights measured in stone
| Measure | Stone (st) | Kilogram (kg) |
|---|---|---|
| Quarter, an old imperial unit | 2 | 12.7006 |
| Highland games heavy weight throw (men) | 4 | 25.4012 |
| Long hundredweight, the old UK coal-sack size | 8 | 50.8023 |
| US hundredweight of 100 lb | 7.1429 | 45.3592 |
| US short ton of 2,000 lb | 142.8571 | 907.1847 |
| Imperial long ton | 160 | 1,016.05 |
Quick mental estimate
Count each stone as 6⅓ kg: 12 st → 72 + 4 = 76 kg. Using 6⅓ in place of 6.35029318 puts the answer about 0.3% low, roughly 0.2 kg for a 12-stone adult.
Use the converter or the charts when the exact figure matters.
The two units
Stone (st): A stone is 14 pounds, exactly 6.35029318 kilograms. In the UK and Ireland body weight is still commonly given in stone and pounds, such as 11 st 4 lb.
Kilogram (kg): The kilogram is the SI base unit of mass. Since 2019 it has been defined by fixing the value of the Planck constant, replacing the platinum-iridium prototype kept near Paris.
Frequently asked questions
How do I convert 11 st 4 lb to kilograms?
Turn it into pounds first: 11 × 14 + 4 = 158 lb. Multiply by 0.45359237 to get about 71.7 kg. You can also type 11.2857 into the stone box, since 4 lb is 4/14 of a stone.
Why do UK doctors record weight in kilograms?
Clinical records and medicine doses in the UK use metric units, and many doses are calculated per kilogram. A patient who knows their weight only in stone can convert it here, but the record uses the reading from the clinic's own scale.
Has the stone always meant 14 pounds?
No. Before weights were standardized, a stone could mean different numbers of pounds depending on the goods, such as wool, meat or cheese. The 14 lb stone became the legal standard in Britain in the 19th century and survives today mainly for body weight.
How precise is the result?
The converter uses the exact definitions above with browser floating-point arithmetic and shows up to 12 significant digits. The charts round to four decimal places for reading.
Sources
Last updated:
Page address with these inputs: https://kakao.mobile/tools/stone-to-kilogram-converter/
Cite or embed this tool
kakaoCalc. (2026, November 8). Stone to Kilograms Converter (st to kg). https://kakao.mobile/tools/stone-to-kilogram-converter/
“Stone to Kilograms Converter (st to kg).” kakaoCalc, 8 Nov. 2026, kakao.mobile/tools/stone-to-kilogram-converter/.
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