Select a category and enter your values below
To convert from Stone (st) to Kilogram (kg), use the following formula:
With is the ratio between the base units Gram (g) and Pound (lb).
Let's convert 5 Stone (st) to Kilogram (kg).
Using the formula:
Therefore, 5 Stone (st) is equal to Kilogram (kg).
Here are some quick reference conversions from Stone (st) to Kilogram (kg):
| Stones | Kilograms |
|---|---|
| 0.000001 st | kg |
| 0.001 st | kg |
| 0.1 st | kg |
| 1 st | kg |
| 2 st | kg |
| 3 st | kg |
| 4 st | kg |
| 5 st | kg |
| 6 st | kg |
| 7 st | kg |
| 8 st | kg |
| 9 st | kg |
| 10 st | kg |
| 20 st | kg |
| 30 st | kg |
| 40 st | kg |
| 50 st | kg |
| 100 st | kg |
| 1000 st | kg |
| 10000 st | kg |
For all Weight converters, choose units using the From/To dropdowns above.
The stone (st) is a unit of measurement equal to 14 pounds (lb).
It's part of the imperial system and is still commonly used in a few countries, especially for weighing people.
For use in international contexts or scientific applications, the stone is often converted to the metric system.
One stone is equal to exactly 6.35029318 kilograms (kg).
This precise conversion is used in international trade and science to ensure everyone is using the exact standard measurement.
Although it's an older unit, the stone remains the primary unit of measurement for body weight in the United Kingdom and Ireland.
It's common to hear someone state their weight as a combination of stone and pounds, like "12 stone 6 pounds."
The stone traces its origins back to the medieval English wool trade, where a "stone of wool" referred to a standard 14-pound measure used for buying and selling.
Stones for other goods could vary in weight—for example, a stone of glass was just 5 pounds—but over time, the 14-pound stone became the official legal standard.
A kilogram (kg) is the base unit of mass in the metric system, used worldwide to measure everything from your body weight to the groceries you buy.
It's equal to 1,000 grams (g).
For a simple real-world comparison, the mass of a one-liter bottle of water is almost exactly one kilogram.
Key Takeaways
For more than 130 years, the kilogram was a physical object: a platinum-iridium cylinder called the International Prototype Kilogram (IPK), also known as "Le Grand K," which was kept under tight security near Paris.
Scientists eventually found the problem — the artifact was losing an imperceptible amount of mass over time — so it couldn't guarantee the long-term accuracy required by science and industry.
On May 20, 2019, the kilogram was redefined.
It's no longer tied to a single object but to a fundamental constant of nature: the Planck constant (h). That change makes the kilogram stable and reproducible with precision anywhere in the universe.
The kilogram's story begins during the French Revolution with the creation of the metric system. The original definition, established in 1795, was beautifully simple and practical.
The gram was first defined as the mass of one cubic centimeter of water at 4 °C (39.2 °F), the temperature at which it is most dense.
From there, the kilogram was defined as the mass of one liter (one cubic decimeter) of water under the same conditions. This practical, water-based definition was a revolutionary step toward a global standard of measurement.
The International System of Units (SI) is built on seven base units that serve as the foundation for all measurements. These include the meter for length, the second for time, and the ampere for electric current.
The kilogram is a historical oddity, as it's the only SI base unit with a prefix ("kilo").
Due to its origins, the kilogram, rather than the gram, became the fundamental unit of mass, making it a curious exception in the measurement system.