Convert pounds to stones

The pound is the base unit of mass in the imperial system and it carries a hard definition: it weighs exactly 0.45359237 kilograms.[1] The United States, the United Kingdom and Ireland all work from that same value.

The stone is the larger unit. Fourteen pounds make one stone, which comes to 6.35029318 kilograms.[2] A pound is therefore a fourteenth of a stone, and that ratio drives every figure on this page.

The split between the two units is geographic. An American gives body weight in pounds alone. A British or Irish speaker divides the same number into whole stones and a pound remainder. Converting pounds to stones is a move from the American notation to the British one.

One pound is 0.0714 stone, a fourteenth. The formula has a single step: stones = pounds ÷ 14.

Across typical body weights the results look like this. A hundred and forty pounds comes to exactly 10 stone. A hundred and eighty pounds comes to 12.8571 stone. Three hundred pounds comes to 21.4286 stone.

The range that covers adult body weight starts in practice around a hundred pounds and reaches three hundred. The lower end is a little over seven stone, the upper a little over twenty-one. The table below covers all of it.

The decimal result suits comparisons and spreadsheets. In conversation in Britain and Ireland the weight is given in the two-unit notation, and the next section covers it.

The opposite direction is handled by the stones to pounds converter, and the move into metric by the pounds to kilograms converter.

The British notation comes out of the decimal result in two steps. The figure before the point is the whole stones. The part after the point, multiplied by 14, gives the pound remainder.

Take 180 pounds. Dividing by fourteen gives 12.8571 stone, so there are twelve whole stones. The fractional part 0.8571 multiplied by fourteen gives twelve pounds. The whole weight reads 12 st 12 lb.

A second route runs through the remainder of the division and suits mental arithmetic. Twelve stone is 168 pounds, and twelve is left over from a hundred and eighty. The answer comes out the same.

Nine values in the table below land on whole stones with no remainder at all: 112, 126, 140, 154, 168, 182, 196, 210 and 280 pounds. Each of them divides by fourteen exactly.

The converter works with the avoirdupois pound of 453.59237 grams, and the field label says so directly: it reads “Pounds (lb)”.

English keeps a second pound in circulation. The troy pound weighs 373.24172 grams and holds twelve troy ounces. The ounce inside it is the unit gold, silver and platinum are priced in.[3] A stone is built from avoirdupois pounds, and that is the pound the field above works in.

The full set of nine pounds from various countries and eras sits in a table on the stones to pounds converter.

A bare pound figure usually points to the United States: that is how an American medical record, training app or equipment listing states weight. A two-unit figure points to Britain and Ireland.

The second source is sport, where the stone remains in daily use: professional boxing, wrestling and horse racing.[2] Weight limits are announced in pounds, and British commentary reads them back in stones.

In stones they then fall on whole and half values. The flyweight limit is 112 pounds, exactly eight stone. The featherweight limit is 126 pounds, exactly nine.[4]

Two divisions land on half stones. Welterweight stops at 147 pounds, ten and a half stone. Light heavyweight stops at 175 pounds, twelve and a half. The table below gives the full set in both notations.