Stone to Kilogram
st
kg
Conversion History
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|---|---|---|
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Quick Reference Table (Stone to Kilogram)
| Stone (st) | Kilogram (kg) |
|---|---|
| 6 | 38.10175908 |
| 7 | 44.45205226 |
| 8 | 50.80234544 |
| 9 | 57.15263862 |
| 10 | 63.5029318 |
| 11 | 69.85322498 |
| 12 | 76.20351816 |
| 13 | 82.55381134 |
| 14 | 88.90410452 |
About Stone (st)
The stone (st) is a unit of weight equal to 14 pounds (approximately 6.35 kg), used almost exclusively in the United Kingdom and Ireland for expressing human body weight. A person weighing 70 kg is approximately 11 stone. The stone is rarely used outside body weight — commercial goods, food, and science all use kilograms in the UK. The stone is not part of the metric system and has no formal SI equivalent; its continued use is a cultural habit, particularly in older generations and media coverage of boxing and fitness.
Average UK adult body weight is often quoted as 11–13 stone. A jockey must typically weigh under 8.5 stone to compete.
Etymology: From the practice of using actual stones as counterweights on balance scales. Standardised in England at 14 pounds by the Weights and Measures Act 1835.
About Kilogram (kg)
The kilogram (kg) is the SI base unit of mass and the standard unit of weight for everyday use worldwide. Since 2019, it is defined by fixing the Planck constant (h = 6.62607015 × 10⁻³⁴ J·s), replacing the previous physical prototype kept in Sèvres, France. The kilogram is the only SI base unit still bearing a prefix ("kilo-") in its name. It is used for body weight, food packaging, luggage limits, and commerce in virtually every country that has adopted the metric system — which is all countries except the United States, Myanmar, and Liberia for everyday use.
A typical laptop weighs 1.5–2 kg. A standard bag of sugar is 1 kg. The average adult human brain weighs about 1.4 kg.
Etymology: From the French "kilogramme" (1795), combining the Greek "khilioi" (thousand) + "gramma" (small weight). The kilogram replaced older weight standards at the adoption of the metric system.
Stone – Frequently Asked Questions
How many pounds are in a stone?
One stone equals exactly 14 pounds. A person who weighs 10 stone weighs 140 pounds (63.5 kg). To convert stone to kilograms, multiply by 6.35; to convert to pounds, multiply by 14.
Do people outside the UK use stone for weight?
Stone is used in the UK and Ireland for body weight but is virtually unknown elsewhere. Australians, Canadians, and New Zealanders — who all once used it — have largely switched to kilograms. Americans use only pounds. If you quote your weight in stone outside the British Isles, expect blank looks.
Why is a stone 14 pounds?
The stone historically varied between 8 and 26 pounds depending on the commodity (wool, meat, cheese). The 14-pound standard was established by the English Weights and Measures Act of 1835, partly because 14 divides evenly into the 28-pound quarter and the 56-pound half-hundredweight.
Is stone used in medical settings in the UK?
The NHS officially uses kilograms in clinical contexts, and most medical equipment is calibrated in kg. However, many patients still report their weight in stone, so UK healthcare professionals routinely work in both systems. Obesity classifications (BMI categories) are always calculated in kilograms.
How do I convert my weight from kilograms to stone and pounds?
Divide your weight in kg by 6.35 to get stone. The whole number is your stone value; multiply the decimal remainder by 14 to get the remaining pounds. Example: 75 kg ÷ 6.35 = 11.81 stone → 11 stone and (0.81 × 14) ≈ 11 lbs, so 75 kg ≈ 11 stone 11 lbs.
Kilogram – Frequently Asked Questions
How many pounds are in a kilogram?
One kilogram equals approximately 2.20462 pounds. For quick mental conversion, multiplying kg by 2.2 gives a close result. To go the other way, divide pounds by 2.2 (or multiply by 0.4536) to get kilograms.
What is the difference between kg and lbs?
Kilograms (kg) are the metric unit of mass used in most of the world; pounds (lbs) are the US customary and imperial unit. 1 kg ≈ 2.205 lbs. Body weight is expressed in kg in most countries and in lbs in the United States, which causes frequent confusion in medical, fitness, and travel contexts.
Why was the kilogram redefined in 2019?
The original kilogram was defined as the mass of a physical platinum–iridium cylinder (the International Prototype Kilogram, or IPK) stored in France. The problem was that the IPK's mass drifted over time relative to official copies. In 2019, the kilogram was redefined using the Planck constant — a fundamental constant of nature — making it stable, universally reproducible, and independent of any physical object.
What is the kilogram used for in everyday life?
The kilogram is used to express body weight, grocery and produce weight, luggage allowances on flights (typically 20–30 kg checked baggage), sports equipment weight limits, and most commercial goods. In science and engineering, it is the base unit for force (newtons), pressure (pascals), and energy (joules) calculations.
How much does a liter of water weigh in kilograms?
One liter of pure water weighs almost exactly 1 kilogram at 4°C (the temperature of maximum density). At room temperature (20°C) it is 0.998 kg — effectively 1 kg for most purposes. This relationship between liter and kilogram is not a coincidence: the liter was originally defined to make it exact.