Stone to Lbs Converter

A stone is a British unit of weight equal to exactly 14 pounds¹. People in the UK and Ireland often give their weight in stone and pounds, such as 11 st 7 lb. US forms, gym apps and many calorie tools ask for pounds or kilograms only, so this converter turns stone and pounds into total pounds and kilograms.

What Stone to Pounds Conversion Measures

This tool changes the unit, not the weight. 11 st 7 lb and 161 lb are the same weight written two ways. It does not weigh you or judge your weight.

The Formula

Two defined numbers do all the work. The stone is defined as 14 pounds, and the pound is defined as exactly 0.45359237 kg¹ ².

Total pounds = (stone x 14) + pounds

Kilograms = total pounds x 0.45359237

One stone = 14 x 0.45359237 = 6.35029318 kg

How This Calculator Computes Your Result

Type your stone and extra pounds in the two boxes. The stone box also accepts decimals, so 11.5 works. A pounds box of 14 or more rolls into stone, so 0 st 20 lb becomes 1 st 6 lb. Nothing is rounded until the end. Kilograms and decimal stone show 2 decimals, and total pounds shows up to 2 (161 lb, 167.5 lb). The tool accepts 1 lb to 1,400 lb (100 st).

What Your Result Means

You get total pounds, kilograms and decimal stone. To check by hand, multiply the whole stone by 14 and add the extra pounds: 11 st 7 lb is 154 + 7 = 161 lb. One stone is about 6.35 kg, so 11 stone is just under 70 kg. Whole stones from 5 to 25 are below.

Where the Stone Is Still Used

The stone began as a local reference weight, often a good-sized rock, and it ranged from 4 to 32 pounds depending on the item. A royal statute of 1389 fixed the wool stone at 14 pounds³. Today it survives mainly for body weight. UK law still defines it as 14 pounds, but lists it among units not to be used for trade except as a supplementary indication².

In a 2022 YouGov poll, 72% of Britons described their weight in stone and pounds and 24% used kilograms. Adults aged 18 to 29 were almost evenly split⁴. In Ireland, a BMI chart for primary care staff gives weights in stone and pounds next to kilograms⁵. The NHS BMI calculator has separate stone and pounds boxes⁶, but many US and calorie tools do not, so convert first.

The Decimal Stone Mistake

The most common slip is reading the number after the point as pounds. It is not. Half a stone is 7 pounds, so 11.5 st is 11 st 7 lb, which is 161 lb. It is not 11 st 5 lb, which is 159 lb. The part after the point is a fraction of 14, not a count of pounds.

To avoid this, put the whole stone in the stone box and the leftover pounds in the pounds box.