Stones to Kilograms
An instant stones-to-kilograms converter, with the formula and a reference table below.
| Stones | Kilograms |
|---|---|
| 1 st | 6.350293 kg |
| 2 st | 12.700586 kg |
| 3 st | 19.05088 kg |
| 5 st | 31.751466 kg |
| 10 st | 63.502932 kg |
| 25 st | 158.757329 kg |
| 50 st | 317.514659 kg |
| 100 st | 635.029318 kg |
How to use
- Enter a value in the Stones field.
- The Kilograms figure appears immediately — no button to press.
- Typing in the Kilograms field converts back to Stones the same way.
- Use the reference table for the values that come up most often.
Stones to Kilograms formula
The factor from stones to kilograms is 6.35029318.
kg = st × 6.35029318
Why this factor: the stone and the kilogram are both defined against the kilogram, so dividing one definition by the other gives 6.35029318 directly. Both definitions are set out in full below.
To go the other way, divide by 6.35029318 — or use the Kilograms to Stones converter, which is the same calculation reversed.
Worked example
Given 150 st, multiplying by 6.35029318 yields 952.543977 kg.
150 st × 6.35029318 = 952.543977 kg
The converter above does this for any value you type, in either direction.
What is a stone?
A stone is fourteen pounds, still the customary unit for body weight in Britain and Ireland.
Definition: Fourteen avoirdupois pounds, so exactly 6.35029318 kilograms.
Where it is used: Personal body weight in the UK and Ireland, where weight is usually given as stones and pounds.
Worth knowing: Effectively unused in the United States, where body weight is quoted in pounds alone.
What is a kilogram?
The kilogram is the SI base unit of mass — the reference for every other mass unit.
Definition: Since 2019 the kilogram has been defined by fixing the Planck constant at exactly 6.62607015×10⁻³⁴ joule-seconds, retiring the physical platinum-iridium cylinder that defined it for 130 years.
Where it is used: Universal in science, trade and everyday weighing outside the United States.
Stones vs Kilograms
The stone is an imperial unit while the kilogram is an SI unit. That is why the factor between them is not a round number: the two systems were defined independently and only later tied together by exact agreement.
Frequently asked questions
How many kilograms are in a stone?
One stone equals 6.35029318 kilograms.
What is the formula to convert stones to kilograms?
Multiply the number of stones by 6.35029318. To reverse it, divide by 6.35029318 instead.
How do I convert kilograms back to stones?
Divide by 6.35029318, which is the same as multiplying by 0.157473044.
How many kilograms are in 10 stones?
10 st works out to 63.502932 kg.
Is there anything to watch out for with stones?
Effectively unused in the United States, where body weight is quoted in pounds alone.
How is the stone defined?
Fourteen avoirdupois pounds, so exactly 6.35029318 kilograms.