A stone is a unit of weight used primarily in the United Kingdom and Ireland to measure body weight. One stone equals 14 pounds or approx. 6.35 kilograms. It's not part of the official metric or imperial systems, but it remains a widely recognized standard in health, fitness, and everyday conversation in the UK. If someone says they weigh "11 stone," they mean 154 pounds (11 × 14).
The stone has historical roots going back to ancient Europe, where stones of specific weight were used in trade. Over time, England standardized the stone to mean 14 pounds in 1835, and that value is still used today. While most countries have adopted the metric system, the stone remains part of British culture—primarily when referring to personal weight.
How is the Stone Used: The stone is most commonly used to express body weight in the UK and Ireland. You'll often hear weights given in stone and pounds together, like "11 stone 4 pounds" instead of 158 pounds or 71.6 kg. It's rarely used in scientific, industrial, or commercial applications today. The metric system has replaced it in those contexts.
A tonne, also known as a metric ton, is a unit of mass equal to 1,000 kilograms or approximately 2,204.62 pounds. It's the standard ton used in most countries that follow the metric system, including Europe, Asia, Australia, and many parts of Africa. Unlike the US ton (short ton, 2,000 lbs) or the UK imperial ton (long ton, 2,240 lbs), the tonne is based on powers of ten, making it more consistent with the metric system. It's used in industries where large-scale weight measurement is common, such as shipping, agriculture, and waste management.
The tonne originated in France in the 18th century as part of the adoption of the metric system. The word comes from the French word "tonneau," which referred to a large cask used for transporting wine or oil.
It became widely accepted across Europe and eventually by the International System of Units (SI). Today, it's the standard unit for mass in global trade, environmental reporting, and scientific documentation.
How is the Tonne Used: The tonne is used to measure very large weights where smaller units like kilograms or pounds would be impractical. You'll find it commonly used in:
1 st = 0.00635 t
Let’s say you want to convert 100 st to t.
Using the formula:
100 × 0.00635 = 0.635 t
So, 100 st is approximately 0.635 t.
| Stone (st) | Tonne (t) |
|---|---|
| 1 st | 0.006 t |
| 2 st | 0.013 t |
| 3 st | 0.019 t |
| 4 st | 0.025 t |
| 5 st | 0.032 t |
| 6 st | 0.038 t |
| 7 st | 0.044 t |
| 8 st | 0.051 t |
| 9 st | 0.057 t |
| 10 st | 0.064 t |
| 11 st | 0.07 t |
| 12 st | 0.076 t |
| 13 st | 0.083 t |
| 14 st | 0.089 t |
| 15 st | 0.095 t |