Tonnes to stone:
multiply by 157.473

How many stone are in a tonne?

One metric tonne is 157.4730444 stone, or about 157.5 stone. A tonne is 1,000 kilograms, and a stone is 6.35029318 kg, so 1,000 divided by 6.35029318 gives the factor.

The tonne here is the metric one, written t or MT. It is not the same as the British long ton or the American short ton, which are defined in pounds.

The metric tonne is an everyday unit for cargo, crops and vehicles, while the stone is a human-scale unit that belongs to British body weights and some older trade records. Converting from one to the other is rare, but it does come up in writing, quizzes and comparisons that need a feel for scale. Expressing a heavy object in stone tells a UK reader roughly how many people's worth of weight it is. A tonne equals about 157 stone, or the weight of around a dozen adults of average build. The factor is not rounded in the converter, so you can trust it for anything from a school exercise to a freight estimate.

The tonne to stone formula

A smaller case works too. Half a tonne is 0.5 × 157.4730444 = 78.7365 stone. Because a stone is about 6.35 kg, you can roughly check this: 500 kg divided by 6.35 is about 78.7.

1. 1Write the weight in tonnes. If it is in kilograms, divide by 1,000.
2. 2Multiply by 157.4730444.
3. 3Round sensibly: whole stone for large loads.
4. 4Check the result against kilograms divided by 6.35.

Chart: tonnes to stone

When tonnes to stone is needed

• Comparing the mass of vehicles, cargo or livestock quoted in tonnes with older British figures given in stone.
• Writing for a UK audience that thinks in stone about a weight published in tonnes, such as an elephant of about 5 to 6 tonnes.
• History and heritage work, where old records list goods in stone and modern sources use tonnes.
• Estimating how many people's worth of body weight a load equals: 1 tonne is about 157 stone.

A truck carrying 12 t is 12 × 157.4730444 = 1,889.68 stone.

Quick sanity checks for tonnes to stone

Each kilogram is 0.1574730444 stone, so a tonne of 1,000 kg gives 157.47 stone directly. A quarter of a tonne is 39.37 stone.

A van payload of 1.2 t is 1.2 × 157.4730444 = 188.97 stone, which is 1,200 kg divided by 6.35.

If you find yourself with a result near 160 times the tonne figure, you are in the right range.

Common mistakes when converting tonnes to stone

• Confusing tonne with ton. A UK long ton is 2,240 lb, or 160 stone exactly, while a metric tonne is 157.47 stone.
• Using the wrong direction. Stone numbers are about 157 times larger than tonnes numbers.
• Dividing by 6.35 without first turning tonnes into kilograms.
• Rounding the factor to 157 on very large loads. On 1,000 tonnes this loses about 473 stone.