Stone to Pounds Converter

One stone is 14 pounds, exact in UK law

A stone is 14 pounds, a definition rather than a measurement. The Weights and Measures Act 1985, Schedule 1 states it in one line, Stone = 14 pounds, and fixes the pound beside it at 0.45359237 kilogram. The NIST Handbook 44, Appendix C repeats the same chain, 14 pounds to a stone, 2 stones to a quarter, 4 quarters to a hundredweight of 112 pounds, 20 hundredweight to a long ton of 2,240 pounds, and notes that the stone is the only one of those old units still in everyday use, kept alive by body weight.

The arithmetic for this page is one multiplication. Pounds = stones x 14. When the weight carries a second number, add it: pounds = stones x 14 + the leftover pounds. Going the other way, stone = pounds / 14, and the remainder of that division is the leftover pounds.

A few checks before the tables: 5 stone is 70 pounds, 8 stone is 112 pounds, and 15 stone is 210 pounds. In metric, 1 stone is 6.35029 kilograms, so 15 stone is 95.25 kilograms.

Read the ladder top to bottom and the place of the stone is clear: it sits between the pound and the hundredweight, and nothing in the United States uses it except imported bathroom scales and British novels.

Reading 11 stone 4: the two number shorthand

British and Irish weights are usually written as two numbers, stones first and pounds second. 11 stone 4 means 11 stone plus 4 pounds: 11 x 14 = 154, then 154 + 4 = 158 pounds, which is 71.67 kilograms. Spoken aloud it is eleven stone four, with the word pounds left out.

The second number runs from 0 to 13 and never reaches 14, because 14 pounds would be another stone. Someone who says 11 stone 15 is describing 12 stone 1, and a dial that shows 11 stone 13 rolls over to 12 stone 0 on the next pound.

The table reads left to right: multiply the stone figure by 14, then add the trailing pounds. Decimal stone works differently and gets its own section below, because 11.4 stone and 11 stone 4 are two different weights.

Stone to pounds chart from 1 to 20 stone

The chart covers the range where stone still shows up, from a big toddler to a heavy adult. Pounds rise by 14 for every row, and kilograms are the pounds figure times 0.45359237.

Two anchors make the chart easy to remember: 10 stone is 140 pounds, and 15 stone is 210 pounds. Every stone above or below those points adds or subtracts 14 pounds, so 13 stone is 182 and 17 stone is 238. For a quick estimate without the chart, round the stone figure to the nearest of those anchors and adjust by 14 pounds per stone.

Stone and kilograms: 6.35029 kg per stone

One stone is 6.35029 kilograms, since 14 x 0.45359237 = 6.35029318. To go from stone to kilograms, multiply by 6.35029; to go from kilograms to stone, divide by 6.35029. The BIPM SI Brochure defines the kilogram, and the pound factor that connects it to stone is the 1959 international agreement value.

Worked examples: 70 kg is 11.02 stone, or 11 stone 0.3, which is why NHS guidance calls 70 kg around 11 stone. 80 kg is 12.60 stone, roughly 12 stone 8.4. 100 kg is 15.75 stone, or 15 stone 10.5. None of those land on round numbers, because 6.35 is not a friendly divisor.

The kg column is what a clinic will file, the stone column is what a patient will say, and the pounds column is what a scale bought in the United States will show. Three numbers, one body.

Why NHS BMI tools and UK clinics ask for stone

The NHS BMI calculator asks for height and weight, and its published example works through 70 kg, described as around 11 stone, at 1.70 metres for a BMI of 24.22. Adults in the United Kingdom often know their weight in stone and pounds while the clinical record stores kilograms, so a nurse converts once at the appointment.

That split explains a common puzzle: a clinic letter lists 71.7 kg while the person at home says 11 stone 4. Both describe the same body, and the small difference comes from rounding the pound figure to one decimal place in kilograms.

Babies are the exception in the other direction. Birth weights are recorded in pounds and ounces, such as 7 lb 8 oz, and health visitors keep that convention well into the first year. The NHS weight pages accept either stones and pounds or kilograms as input, so a figure in stone can go straight into the form without converting first.

Luggage, dog weights and scales that only show stone

Baggage rules are written in kilograms, veterinary charts use kilograms for large animals and pounds for small ones, and older bathroom scales are marked in stone alone. Converting each to pounds keeps the comparison honest, because the airline, the vet and the dial all mean the same force on the same spring.

On a mechanical scale marked in stones with single pound ticks, read the last whole stone below the pointer and count the ticks after it. A pointer sitting four ticks past the 11 mark is 11 stone 4, or 158 pounds. Digital scales sold in the UK usually toggle between stone, pounds and kilograms with a button on the base, so the same person can be 11 st 4 one morning and 158 lb the next without any change in weight.

Half a stone, a quarter stone, and weight loss talk

Weight changes in Britain are spoken in fractions of a stone, not in pounds. Half a stone is 7 pounds, a quarter stone is 3.5 pounds, and three quarters is 10.5 pounds. Dropping a stone means dropping 14 pounds, and dropping two stone means 28.

The phrases carry the same meaning in newspapers, slimming groups and gyms. Someone who is nine and a half stone weighs 133 pounds; a stone and a half is 21 pounds; two and a half stone is 35. Boxing follows the same habit, which is why a fighter campaigning at the 154 pound limit is listed at 11 stone, and why a weigh in sheet with 11 st 4 on it describes a 158 pound fighter, 4 pounds above that limit.

Decimal stone is not stone and pounds

Most wrong answers on this conversion come from four habits that are easy to fix.

• Reading 11.4 stone as 11 stone 4. The decimal is a fraction of a stone, so 11.4 x 14 = 159.6 pounds, while 11 stone 4 is 158. The gap is 1.6 pounds, and 159.6 pounds is 11 stone 5.6.
• Using 16 instead of 14. Sixteen is the ounce count in a pound, not the pound count in a stone. A 16 pound stone turns 11 stone 4 into 180 pounds, 22 pounds too high.
• Forgetting the leftover pounds. 12 stone alone is 168 pounds; 12 stone 7 is 175. Dropping the 7 loses half a stone.
• Rounding the kilogram factor to 2. One kilogram is 2.20462 pounds, so 70 kg is 154.32 pounds, not 140.

A long ton is 160 stone, since 2,240 / 14 = 160, and that is the only place where stone meets a unit larger than itself in ordinary use. Check any answer by multiplying the stone figure back out: 158 pounds divided by 14 gives 11 with 4 left over, which returns the original 11 stone 4.