Stone to Pounds Converter

stone to pounds — quick reference

The formula, worked line by line

There is no constant to look up here. A stone is defined as fourteen avoirdupois pounds, a whole number chosen by statute rather than derived from a physical prototype, so the conversion is a single multiplication that can be done in your head and checked on paper without a calculator anywhere in the loop.

What the pound itself weighs is a separate question with a separate answer, and it is the one that carries the exact decimal. The 1959 International Yard and Pound Agreement fixed the avoirdupois pound at 0.45359237 kilograms, which is why a stone comes out at 6.35029318 kilograms and why that figure has eight decimal places rather than a tidy two.

pounds = stone × 14
11 st → 11 × 14 = 154 lb
pounds = (stone × 14) + leftover pounds
11 st 4 → (11 × 14) + 4 = 158 lb
kilograms = pounds × 0.45359237

Fourteen is easier than it looks

Multiplying by 14 has a shortcut worth knowing, because it comes up every time someone reads a British weight aloud. Multiply by 10, then add four times the number. For 12 stone: 120, plus 48, is 168. For 9 stone: 90, plus 36, is 126. It is faster than doubling repeatedly and it never needs a written column.

The stone has no American equivalent

The United States never adopted the stone for everyday use, even though it inherited the same avoirdupois pound. American body weight is quoted in plain pounds, so a US scale simply shows 154 and no conversion is needed once you have arrived at the pound figure. Canada, Australia and New Zealand use kilograms for the same purpose.

That asymmetry is why this conversion is so lopsided in practice: a British reader almost never needs to turn stone into pounds, because their own scale shows both. It is the American, or the person reading a British source, who needs the multiplication, and who then needs to know that the leftover pounds were being spoken separately all along.

How to use the stone to pounds converter

Someone has quoted a weight in stone and you need it in pounds. That is nearly always the situation on this page: a British or Irish figure has landed in front of an American reader, in a novel, a news report, a medical form, a sports result or a message from a relative, and the unit means nothing until it is translated.

The arithmetic is the easiest conversion on this site. A stone is exactly 14 pounds, a whole number rather than a measured constant, so every whole stone converts to a whole number of pounds and the conversion introduces no rounding at all. 11 stone is 154 pounds, 12 stone is 168, and each extra stone adds another 14.

The part that actually trips people up is not the multiplication, it is the reading. British and Irish weights are spoken as two numbers, whole stone and leftover pounds, exactly the way American heights are spoken as feet and inches. Nobody says five point eight feet, and nobody says eleven point two nine stone either.

For a rough mental version, multiply the stone by 14 by doubling three times and subtracting twice the original: 11 doubled is 22, then 44, then 88, plus 2 times 11 which is 22, giving 154. Most people find it easier to take 10 stone as 140 pounds and count on in fourteens from there.

Reading a British weight out loud

The convention is fixed and it is worth learning once. Whole stone comes first, leftover pounds second, and the pounds are never spoken as a fraction of a stone. Ten stone seven is 147 pounds. Nine stone thirteen is 139 pounds. The pounds figure runs from zero to thirteen and then the stone count goes up by one.

Half a stone is 7 pounds, so the phrase eleven and a half stone means 161 pounds. Quarter stone is not used in speech, and neither is any smaller fraction. A stone reading is almost never given to a decimal, which is why an American encountering 11.29 stone should assume the conversion has already gone wrong somewhere upstream.

Written forms vary and all of them mean the same thing. You will see 11st 4lb, 11 st 4, 11-4 and simply eleven four in casual speech. The unit abbreviation st is lower case and takes no plural s in British usage, so eleven stone rather than eleven stones, though the plural does turn up in older writing.

Why the stone survives in a metric country

The stone is a legal curiosity. The United Kingdom uses metric units for trade, and the Weights and Measures Act 1985 does not list the stone among the units permitted for use in trade, which means you cannot legally sell anything by the stone. What the law never attempted was to change how people talk, and body weight in the UK and Ireland is still spoken and thought about in stone.

The unit also predates any of that by centuries and used to be far messier. Before standardization a stone varied by commodity and by region, from around 8 pounds to 24, so a stone of wool and a stone of meat were different quantities. The Weights and Measures Act 1835 settled the general stone at fourteen pounds, and it has been exactly that ever since.

Practically, this means an American reader will meet the stone in exactly the places where speech rather than commerce is doing the work. Personal conversation and social media. British and Irish fiction and journalism. Health advice aimed at the public, where the National Health Service routinely gives weights in stones and pounds alongside kilograms. British horse racing, which still carries weights in stones and pounds.

Every stone value, worked out

30 common stone figures each get their own page, with the answer at full precision, the arithmetic, what rounding costs, and the nearest real-world reference point on the scale.

Questions people ask