What is a stone in weight?

A stone (st) is a British unit of weight equal to 14 pounds (6.35029 kg). It is used primarily in the UK and Ireland for measuring body weight.

Why do the British use stones?

The stone has deep historical roots in British commerce and daily life. Though the UK officially adopted the metric system, the stone persists for body weight as a matter of cultural habit, similar to how Americans continue using Fahrenheit despite the global preference for Celsius.

How many stones is 150 pounds?

150 pounds equals 10 stones 10 pounds (150 ÷ 14 = 10 remainder 10). In decimal, it is approximately 10.71 stones.

What Is a Stone? The UK Weight Unit Explained

Definition

A stone (symbol: st) is a unit of weight in the imperial system equal to 14 avoirdupois pounds (6.35029318 kg).

History

The stone has been used in trade since ancient times, but its exact weight varied by commodity and region. A "stone of wool" was 14 pounds, a "stone of butcher's meat" was 8 pounds, and a "stone of glass" was 5 pounds. In 1835, the British Weights and Measures Act standardized the stone at exactly 14 pounds for all purposes.

Conversion Table

Stones	Pounds	Kilograms
8	112	50.8
9	126	57.2
10	140	63.5
11	154	69.9
12	168	76.2
13	182	82.6
14	196	88.9
15	210	95.3

Where It Is Used Today

The stone is used almost exclusively for human body weight in the UK and Ireland. British people commonly say "I weigh 11 stone" rather than "I weigh 154 pounds" or "70 kg." It is not used in the United States, Canada, or Australia, and it is not an official SI unit.

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