What this calculator does
Height in feet and inches and weight in stone and pounds are compound units, made of two numbers that carry at 12 and 14 rather than at 10. That is what makes them awkward to convert: the two parts have to be reduced to a single quantity first, then converted, and the reverse needs a division with a remainder.
The stone is the one that confuses outside Britain and Ireland. It is 14 pounds, so 11 stone 8 is 162 pounds, and both are about 73.5 kg. Most of the world uses kilograms, the United States uses pounds alone, and only a few countries still use stone, which is why the same weight gets quoted three different ways.
The formula
Height is converted by taking the feet as 30.48 cm each and the inches as 2.54 cm each, then adding them. Weight takes the stone as 6.35029 kg each and the pounds as 0.453592 kg each. Both factors are exact by international agreement, since the inch and the pound were formally defined against the metre and the kilogram in 1959. The height check line converts back to feet and inches as a confirmation that nothing was lost.
| Term | Meaning |
|---|---|
| Foot | 12 inches, exactly 30.48 cm. |
| Inch | Exactly 2.54 cm, fixed by international agreement in 1959. |
| Stone | 14 pounds, about 6.35 kg. Used for body weight in Britain and Ireland. |
| Pound | Exactly 0.45359237 kg. |
The inputs explained
| Field | What to enter |
|---|---|
| Feet | The feet part of a height. |
| Inches | The inches part, from 0 to 11. Values of 12 or more will still convert correctly but are better carried into the feet. |
| Stone | The stone part of a weight. |
| Pounds | The pounds part, from 0 to 13. For a weight given in pounds alone, leave stone at 0 and enter the whole figure here. |
When to use it
Filling in a form that wants the other system
Medical, travel and sporting forms ask for whichever system they were written for, and a conversion done in a hurry is a common source of a wrong figure on a record that matters.
Reading a height or weight quoted abroad
A height in centimetres means little to someone raised on feet and inches and the reverse is equally true, so the conversion is mostly about making a figure intelligible rather than precise.
Converting a weight given in pounds alone
US weights are in pounds with no stone, so leaving the stone field at zero and entering the whole figure in pounds handles that case directly.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
What are common heights in centimetres?
A height of five feet with the inches increasing, converted to centimetres.
| Inches | Height | Height in metres | Height check |
|---|---|---|---|
| 0 in | 152.4 cm | 1.52 m | 5′ 0.0″ |
| 3 in | 160.0 cm | 1.60 m | 5′ 3.0″ |
| 6 in | 167.6 cm | 1.68 m | 5′ 6.0″ |
| 9 in | 175.3 cm | 1.75 m | 5′ 9.0″ |
| 11 in | 180.3 cm | 1.80 m | 5′ 11.0″ |
What are common weights in kilograms?
A weight of a varying number of stone plus 8 pounds, converted to kilograms.
| Stone | Weight | Weight in pounds |
|---|---|---|
| 8 st 8 lb | 54.43 kg | 120.0 lb |
| 10 st 8 lb | 67.13 kg | 148.0 lb |
| 11 st 8 lb | 73.48 kg | 162.0 lb |
| 13 st 8 lb | 86.18 kg | 190.0 lb |
| 16 st 8 lb | 105.23 kg | 232.0 lb |
Questions
How many pounds in a stone?
Fourteen, exactly. So 11 stone 8 pounds is 162 pounds. The stone is only used for body weight and only in a few countries, which is why the conversion is needed so often when reading figures from Britain or Ireland.
How do I convert my height to centimetres?
Multiply the feet by 30.48 and the inches by 2.54, then add them. Five foot nine is 152.4 plus 22.86, which is 175.26 cm. Converting the whole height to inches first and multiplying by 2.54 gives the same answer in one step.
Are the conversion factors exact?
Yes. The inch has been exactly 2.54 cm and the pound exactly 0.45359237 kg since the international agreement of 1959. Any rounding in the result comes from the display rather than from the conversion itself.
My weight is in pounds with no stone. What do I enter?
Leave the stone field at zero and put the whole figure in the pounds field. The calculation adds the two parts, so a single figure in either field converts correctly on its own.
For length and distance beyond height, see the length converter. For weight and mass units generally, see the mass converter.