What is a kilograms to stones converter?
A kilograms to stones converter is an online tool that turns a weight expressed in kilograms (kg) into stones (st), and back again. It is especially handy for body weight, where the stone remains a popular everyday unit in the United Kingdom and Ireland even though the rest of the world reports the same figure in kilograms.
The stone is an imperial unit of mass equal to 14 pounds, and one stone is defined as exactly 6.35029318 kilograms. Because people often quote body weight as “11 stone 4”, this converter also gives you the value broken down into whole stones plus the leftover pounds.
The tool is bidirectional: enter a value in any field — kilograms, stones, or pounds — and the other two update automatically.
History of the stone
The stone has a long and uneven history. Across medieval Europe a “stone” referred to a physical lump of rock kept as a local weighing standard, so its value varied widely from town to town and from trade to trade — wool, cheese, and meat each had their own stone. Values ranged from roughly 5 pounds up to more than 30 pounds depending on the commodity and region.
In 1835 the United Kingdom standardised the stone at exactly 14 avoirdupois pounds. Since the avoirdupois pound is itself defined as 0.45359237 kilograms, the stone became fixed at 6.35029318 kg. The unit has since fallen out of legal trade use in most contexts but survives strongly for personal body weight in Britain and Ireland.
How does the calculator work?
The converter relies on two fixed relationships: one stone equals 14 pounds, and one pound equals 0.45359237 kilograms. Combining them, one stone equals 6.35029318 kilograms.
When you enter kilograms, the tool divides by 6.35029318 to get stones and divides by 0.45359237 to get pounds. When you enter stones, it multiplies by 6.35029318 for kilograms and by 14 for pounds. When you enter pounds, it applies the matching factors in reverse.
Formula
The core conversion between kilograms and stones is a single division:
To go the other way, multiply instead:
For the stones-and-pounds breakdown, take the whole-number part as stones and convert the remaining fraction into pounds by multiplying by 14:
Table of units of measurement
| Units of measurement | in kg | in st | in lbs |
|---|---|---|---|
| Stone (st) | 6.35029 | 1 | 14 |
| Kilogram (kg) | 1 | 0.157473 | 2.20462 |
| Pound (lb) | 0.453592 | 0.0714286 | 1 |
Example conversions
Convert 6.35029318 kilograms to stones.
Using the formula:
So 6.35029318 kg equals exactly 1 stone, which is also 14 pounds.
Convert 63.5029318 kg to stones.
Thus 63.5029318 kg equals 10 stones, or 140 pounds.
Notes
- One stone is exactly 6.35029318 kg, so a common rounded shortcut is “1 stone is about 6.35 kg”.
- For a quick mental estimate, dividing kilograms by 6.35 gives a close stone figure.
- Body weight in the UK is usually spoken as stones plus pounds, for example 70 kg is roughly 11 st 0.2 lb.
Frequently asked questions
How many kilograms are in one stone?
One stone equals exactly 6.35029318 kilograms, because a stone is 14 pounds and each pound is 0.45359237 kg.
How do I convert kilograms to stones?
Divide the weight in kilograms by 6.35029318. For example, 50 kg divided by 6.35029318 is about 7.87 stones.
Why is the stone still used?
In the United Kingdom and Ireland the stone is the customary unit for describing a person’s body weight in everyday conversation, even though kilograms are used in medical and scientific settings. If you also want a pounds breakdown, see our stone to pounds converter.
How do I write a weight in stones and pounds?
Take the whole stones first, then multiply the leftover fraction of a stone by 14 to get the remaining pounds. For instance, 7.5 stones is 7 stones and 7 pounds. To move between kilograms and pounds directly, try our kilograms to pounds converter.