To convert kilograms to stone (kg to st), multiply by 0.15747. 1 kilogram equals 0.15747 st, about 2.2 times as much as a loaf of sandwich bread.
| kilograms | stone |
|---|---|
| 1 kilogram | 0.15747 st |
| 2 kilograms | 0.31495 st |
| 5 kilograms | 0.78737 st |
| 10 kilograms | 1.5747304 st |
| 25 kilograms | 3.9368261 st |
| 50 kilograms | 7.8736522 st |
| 100 kilograms | 15.747304 st |
| 250 kilograms | 39.368261 st |
| 500 kilograms | 78.736522 st |
| 1000 kilograms | 157.47304 st |
Definition: The SI base unit of mass - 1,000 grams.
History: For 130 years, the kilogram was defined by a single physical object: a golf-ball-sized cylinder of platinum and iridium nicknamed "Le Grand K," locked in a vault outside Paris and taken out for cleaning only once every 40 years. Every kilogram on Earth was, technically, defined by how much that one specific object weighed - which became a real problem once scientists discovered it had lost about 50 micrograms of mass over its lifetime, for reasons nobody could fully explain. In 2019, the kilogram was redefined using Planck's constant instead, a fundamental property of physics that can't drift, get scratched, or need cleaning.
Current use: The standard unit of mass in nearly every country on Earth, used in science, medicine, and everyday commerce.
Definition: 14 pounds, or about 6.35 kilograms.
History: Started as exactly what it sounds like: a stone used as a physical weight on a scale. Different regions of England once had wildly different "stones," ranging anywhere from 5 to 40 local pounds depending on what was being weighed and where. The 14-pound version was formally fixed into English law in 1835, well after most other regional stones had already been standardized away.
Current use: Almost exclusively body weight in the UK and Ireland - "I weigh 11 stone 4" is completely normal there, and completely opaque everywhere else.
The factor is 0.157473, which is derived rather than defined, so any decimal you see has been rounded somewhere.
No simple round multiplier is close enough to be useful, so this is one to look up rather than estimate. The exact factor is 0.157473.
Going the other way, one stone is 6.35 kg, which is usually the easier direction to work in. Because the forward factor is small, watch the decimal place rather than the digits: a factor-of-ten slip is the common error, not a rounding one.
To anchor the scale: 10 kilograms is about 1.57 st.