Stone to Pounds Converter

Stone to Pounds

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

The Formula

`` pounds = stone × 14 stone = pounds × 0.0714285714286 `

One stone is 14 pounds, and one pound is 0.071429 stone.

Conversion Table

Stone	Pounds
1 st	14 lb
2 st	28 lb
5 st	70 lb
10 st	140 lb
25 st	350 lb
50 st	700 lb
100 st	1,400 lb
500 st	7,000 lb
1,000 st	14,000 lb

The Other Direction

Pounds	Stone
1 lb	0.071429 st
2 lb	0.142857 st
5 lb	0.357143 st
10 lb	0.714286 st
25 lb	1.7857 st
50 lb	3.5714 st
100 lb	7.1429 st
500 lb	35.7143 st
1,000 lb	71.4286 st

What Each Unit Is

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

Pounds (lb) — exactly 0.45359237 kilograms, by the 1959 international agreement. The Roman libra — which is why its symbol is lb — refined through the English avoirdupois system.

A Sense of Scale

• British body weight is often given in stone and pounds
• An adult is typically 9–14 stone
• A bag of sugar is 2 lb
• A newborn is 6–9 lb
• US body weight is given in pounds

Precision

The factor 14 is exact by international agreement, not a rounded approximation. Any imprecision in a result comes from your input, not the conversion.

Watch Out For

• Effectively British-only. US sources give body weight in pounds alone.

In Code

`javascript const stoneToPound = (value) => value * 14; ``

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 st with the factor truncated at each decimal place:

Decimals kept	Factor	137 st becomes	Error
0	14	1,918	—
1	14	1,918	—
2	14	1,918	—
3	14	1,918	—
4	14	1,918	—

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 stone to three significant figures, the answer in pounds is only good to three — writing more digits claims precision the measurement never had.