Pound to Stone Converter

What the pound to stone converter returns

Type a weight in pounds, add ounces if you have them, and the box above hands back four answers at once: the whole stones, the pounds left over, the ounces remaining after that, and one weight as a decimal figure of stones plus kilograms. The stone is not a unit most Americans use, and seeing one weight in all three forms at once is the point.

The conversion itself is one division, given that a stone is 14 pounds. Everything else on the page is bookkeeping around that division: what to do with the remainder, how to say the answer aloud, and how to keep the ounces straight.

Notice how the stone column grows by one for every 14 pounds, and how the leftover pounds never reach 14. If they did, the stone count would be wrong.

One stone is 14 pounds, and the law says so

The stone is an old English weight that survived centuries of different values for different goods. Wool was weighed in 14 pound stones, glass in 5 pound stones, meat and fish in 8 pound stones. The Weights and Measures Act 1824 fixed one imperial pound for the whole United Kingdom, and today's law, the Weights and Measures Act 1985, Schedule 1, states the stone plainly: Stone = 14 pounds. That schedule fixes Pound = 0.45359237 kilograms and Ounce = 1/16 pound, and that is what makes the metric column in the tables below exact, not approximate.

For everyday work the whole rule is one line: divide the pounds by 14. The whole figure part is the stones, and the remainder is the leftover pounds. Since 1 pound is 16 ounces, the leftover pounds can be broken down again into pounds and ounces, and 14 pounds x 16 ounces gives 224 ounces per stone.

The United States never adopted the stone for body weight, meaning an American scale reads pounds while a British one reads stones and pounds. NIST's Special Publication 811, the official guide to SI units, lists the pound as 0.45359237 kilograms exactly.

Worked example: 185 pounds

Take 185 pounds, a common adult weight in pounds that looks awkward in stone. The steps do not change for any figure you start with.

The decimal form, 13.2143 stone, is one answer written a second way. Multiply the 0.2143 part by 14 and you are back to the 3 leftover pounds, given 3 / 14 = 0.2143. The two forms carry identical information, and the choice between them depends on who is reading.

Watch the remainder rule on a bigger figure. 300 pounds divides by 14 to give 21 whole stones, as 21 x 14 = 294, and 6 pounds are left, putting 300 pounds at 21 st 6 lb. No rounding, just a division and a subtraction.

Worked example: 165 pounds 8 ounces

Ounces come up with babies, pets and race entries, and they change the arithmetic slightly. The rule is to fold the ounces into the pounds first, since 16 ounces make a pound.

Start with 8 ounces. Since 0.5 x 16 = 8, the 8 ounces are half a pound, giving a total of 165.5 pounds. Now divide by 14: 165.5 / 14 = 11.8214, leaving 11 whole stones. Multiply back, 11 x 14 = 154, and subtract, 165.5 - 154 = 11.5 pounds left. That leftover is 11 pounds plus half a pound, and half a pound is 8 ounces.

The answer is 11 st 11 lb 8 oz, and it reads exactly the way a British nurse or a boxing trainer would say it. Keep the ounces in ounces until the last step: converting them to a decimal too early is how a 6 ounce error creeps into a weight that matters.

Reference table from 100 to 300 pounds

The rows below cover the range where most conversions happen, from a 100 pound parcel to a 300 pound powerlifter. Whole stones are marked where the pounds divide evenly.

Read the 140 and 280 rows as anchors: each lands on a whole stone, and every 14 pounds above them adds exactly one stone. That makes mental arithmetic possible in both directions, since 140 pounds is 10 stone, 154 pounds is 11 stone, and 168 pounds is 12 stone.

How people say it: 11 stone 4

In Britain the spoken form drops the pounds label. Someone who weighs 165 pounds is 11 stone 11, and the 11 after the stone is understood as pounds. Weights round to whole stones in casual speech, making 11 st 6 lb often just 11 and a half stone, even though 11.5 stone is 161 pounds.

Two habits deserve attention before you quote a figure. First, the plural is usually dropped: people say 15 stone, not 15 stones, though stones does appear in some regions. Second, medicine runs on kilograms. A UK medical record holds weight in kilograms, and the NHS healthy weight guidance asks for weight in either stones and pounds or kilograms for its BMI tools. Bathroom scales sold in the UK show stones and kilograms side by side, while clinic scales usually show kilograms alone.

Babies are the exception in the other direction. Birth weights are given in pounds and ounces, such as 7 lb 8 oz, equal to 7.5 pounds and 3.40 kilograms. The converter handles that case too: enter 7 pounds 8 ounces and it reports 0 st 7 lb 8 oz.

Forms are where the two systems collide. A shipping label may ask for a parcel weight in kilograms while the kitchen scale beside it reads ounces, and a clinic in a border town might want the value in stones and pounds to match the notes on file. Writing 11 st 11 lb 8 oz on a form that wants pounds and ounces needs no conversion at all, and keeping the digits handy matters more than naming the unit.

The old trade names linger in older paperwork too. A stone used for wool, iron or fish could weigh anywhere from 5 to 14 pounds depending on the commodity, one reason a nineteenth century ledger that mentions stones has to be read alongside the trade that produced it. For anything modern, 14 pounds is the only figure that matters.

Sport is the other place the unit survives. Weigh-in sheets for boxers, jockeys, wrestlers and greyhounds still list the stone next to the pound, and a wrestling promotion that quotes a challenger at 14 st 8 lb is describing a wrestler who weighs a shade under 205 pounds. Those sheets record the limit, not the reading, and a heavyweight champion walking around at 15 st is normal and says nothing about the division.

Horse racing still speaks the old language. A jockey who must ride at 8 st 7 lb is carrying 119 pounds, and a handicapper who allots 10 st 2 lb has set a weight of 142 pounds. The weighing room scales read in stones and pounds given that the handicap charts are printed that way, and a trainer converting those figures to kilograms would be working against the rulebook.

Farm work used the stone too, mostly for fleece and for market descriptions of livestock, and the phrase a stone of wool still appears in nineteenth century accounts of harvests. Reading those records today without knowing that the wool stone carried 14 pounds can make a flock sound far smaller than it was.

Luggage, gym plates and vet charts

The pounds to stone direction turns up whenever an American figure meets a British one. The table below is where that happens most.

A suitcase that tips the bathroom scale at 48 pounds is 3 st 6 lb, and a holdall at 20 pounds is 1 st 6 lb. Neither reading changes the airline fee, set in kilograms, but the stone figure is what tells you whether the bag will go into the overhead rack.

The luggage row is the one that surprises travellers. A 23 kilogram checked bag is the worldwide standard, worth 50.71 pounds, or 3 st 8.71 lb. British airline staff think in kilograms, American staff think in pounds, and nobody thinks in stone, but the stone figure is what tells you instantly that the bag passes the 3 stone mark for a carry-on.

Gym plates follow the matching path in reverse. A 45 pound plate is 3 st 3 lb, and a lifter who knows their body weight in stone can add up a total in pounds and still report it in stone without a calculator.

Freight has its own vocabulary for matching arithmetic. A courier quoting a parcel at 66 pounds, a removal firm estimating a piano at 350 pounds, and a breeder shipping a puppy crate at 18 pounds all describe loads that a UK customer will read in stones. The parcel is 4 st 10 lb, the piano is exactly 25 st, and the crate is 1 st 4 lb, letting a quote be tested against a bathroom scale before the van arrives.

The metric side, and five mistakes to avoid

The stone rests on the pound, and the pound rests on the kilogram at an exact ratio: 1 lb = 0.45359237 kg. That makes 1 stone = 6.35029318 kg, and 1 kg = 2.2046 pounds. To go from kilograms to stone, divide the kilograms by 6.35029318, putting 80 kg at 12.5978 stone, or 12 st 8.37 lb. The BIPM measurement units page keeps the SI definitions that the pound factor hangs from.

Five mistakes explain nearly every wrong answer:

• Multiplying by 14 instead of dividing. Pounds to stone goes downward, meaning 185 pounds is 13 stone, and 13 stone x 14 is how you verify it, not how you get there.
• Reading 13.5 stone as 13 st 5 lb. The decimal 13.5 stone is 13 st 7 lb, since 13.5 x 14 = 189 and 189 - 182 = 7.
• Mixing up the 14 and the 16. There are 14 pounds in a stone and 16 ounces in a pound, and the two numbers do not interchange.
• Rounding the leftover away too soon. 50.71 lb is 3 st 8.71 lb, not 3 st 9 lb, if the ounces matter.
• Confusing the stone with the ton. The long ton of 2240 pounds is 160 stone, and 2240 / 14 = 160, a handy sum to remember.

For the opposite direction, the stone to pounds converter multiplies by 14 instead, and the pounds to tons converter handles the far larger units. Metric-minded readers can use the kg to lbs converter, the lbs to kg converter, and the ounce to pound converter for the smaller pieces.