Tons to Stone Converter

Tons to Stone

Convert tons (t) to stone (st). Both measure mass and weight, and the conversion comes up in cooking, shipping, fitness work.

The Formula

`` stone = tons × 157.473044418 tons = stone × 0.00635029318 `

One ton is 157.473 stone, and one stone is 0.00635 tons.

Conversion Table

Tons	Stone
1 t	157.473 st
2 t	314.9461 st
5 t	787.3652 st
10 t	1,574.73 st
25 t	3,936.83 st
50 t	7,873.65 st
100 t	15,747.3 st
500 t	78,736.52 st
1,000 t	157,473.04 st

The Other Direction

Stone	Tons
1 st	0.00635 t
2 st	0.012701 t
5 st	0.031751 t
10 st	0.063503 t
25 st	0.158757 t
50 st	0.317515 t
100 st	0.635029 t
500 st	3.1751 t
1,000 st	6.3503 t

What Each Unit Is

Tons (t) — here the metric tonne: exactly 1,000 kilograms. From the tun, a large wine cask, whose weight became a trade standard.

Stone (st) — exactly 14 pounds, or 6.35029318 kilograms. A medieval trade weight that varied by commodity until standardised at 14 lb in 1835.

A Sense of Scale

• A small car is about 1.5 t
• A cubic metre of water is 1 t
• Shipping freight is priced per tonne
• British body weight is often given in stone and pounds
• An adult is typically 9–14 stone

Precision

The factor 157.473044418 is rounded. For engineering work carry more digits than the table above, and round only at the end — rounding at each step compounds.

Watch Out For

• Three different tons exist: metric (1,000 kg), US short (907 kg) and UK long (1,016 kg). This converter uses the metric tonne.
• Effectively British-only. US sources give body weight in pounds alone.

In Code

`javascript const tonToStone = (value) => value * 157.473044418; ``

Where This Conversion Comes Up

• Cooking
• Shipping
• Fitness
• Medicine
• Manufacturing

How Many Decimals Do You Need?

Rounding the factor costs accuracy, and how much depends on the factor. Converting 137 t with the factor truncated at each decimal place:

Decimals kept	Factor	137 t becomes	Error
0	157	21,509	0.3004%
1	157.5	21,577.5	0.0171%
2	157.47	21,573.39	0.0019%
3	157.473	21,573.8	—
4	157.473	21,573.8	—

A rule that holds for any conversion: round once, at the end. Rounding the factor and then multiplying compounds the error through every subsequent calculation, while carrying full precision and rounding the final answer does not.

The right number of significant figures is set by your input, not by the converter. If you measured tons to three significant figures, the answer in stone is only good to three — writing more digits claims precision the measurement never had.