To convert stone to kg, multiply the number of stone by 6.35029. So 10 stone is 63.5 kg and 12 stone is 76.2 kg. If your weight has pounds as well, turn the whole lot into pounds first, then multiply by 0.453592.
Stone to Kg Converter
Instant, accurate weight conversion
1 stone = 14 pounds = 6.35029 kg • 1 kg = 2.20462 lb
Enter your stone and pounds in the stone to kg converter above and the answer appears straight away. The rest of this page shows the working, a full table and a few shortcuts for when you have no calculator nearby.
How do you convert stone and pounds to kg?
Change your weight into pounds, then multiply the pounds by 0.453592. This works for any weight, with or without spare pounds.
- Multiply your stone by 14. This turns them into pounds.
- Add any extra pounds.
- Multiply the total by 0.453592.
- Round the answer to one or two decimal places.
Here is an example for someone who weighs 11 stone 6 pounds:
- 11 × 14 = 154 pounds
- 154 + 6 = 160 pounds
- 160 × 0.453592 = 72.57 kg
So 11 stone 6 pounds is 72.57 kg, or about 72.6 kg on most scales.
What is the formula for stone to kg?
The formula is: kilograms = stone × 6.35029. If there are pounds too, the full version is: kilograms = (stone × 14 + pounds) × 0.453592.
Both numbers come from the same place. One pound is set at exactly 0.45359237 kilograms, a figure agreed between Britain, the United States and other countries in 1959. A stone is 14 of those pounds, and 14 × 0.45359237 gives 6.35029 kg.
You only need the short version when your weight is a round number of stone. As soon as pounds are involved, use the longer one.
How many kg is each stone from 1 to 25?
Each stone adds 6.35 kg. The table below gives the kilogram figure for every whole stone from 1 to 25, along with the same weight in pounds.
| Stone | Kilograms | Pounds |
| 1 st | 6.35 kg | 14 lb |
| 2 st | 12.70 kg | 28 lb |
| 3 st | 19.05 kg | 42 lb |
| 4 st | 25.40 kg | 56 lb |
| 5 st | 31.75 kg | 70 lb |
| 6 st | 38.10 kg | 84 lb |
| 7 st | 44.45 kg | 98 lb |
| 8 st | 50.80 kg | 112 lb |
| 9 st | 57.15 kg | 126 lb |
| 10 st | 63.50 kg | 140 lb |
| 11 st | 69.85 kg | 154 lb |
| 12 st | 76.20 kg | 168 lb |
| 13 st | 82.55 kg | 182 lb |
| 14 st | 88.90 kg | 196 lb |
| 15 st | 95.25 kg | 210 lb |
| 16 st | 101.60 kg | 224 lb |
| 17 st | 107.95 kg | 238 lb |
| 18 st | 114.31 kg | 252 lb |
| 19 st | 120.66 kg | 266 lb |
| 20 st | 127.01 kg | 280 lb |
| 21 st | 133.36 kg | 294 lb |
| 22 st | 139.71 kg | 308 lb |
| 23 st | 146.06 kg | 322 lb |
| 24 st | 152.41 kg | 336 lb |
| 25 st | 158.76 kg | 350 lb |
Our stone to kg chart has a longer version with every pound in between.
How many kg do the extra pounds add?
Each pound adds 0.454 kg, which is a little under half a kilogram. Find your whole stone in the table above, then add the figure for your spare pounds from this one.
| Pounds | Kilograms |
| 1 lb | 0.45 kg |
| 2 lb | 0.91 kg |
| 3 lb | 1.36 kg |
| 4 lb | 1.81 kg |
| 5 lb | 2.27 kg |
| 6 lb | 2.72 kg |
| 7 lb | 3.18 kg |
| 8 lb | 3.63 kg |
| 9 lb | 4.08 kg |
| 10 lb | 4.54 kg |
| 11 lb | 4.99 kg |
| 12 lb | 5.44 kg |
| 13 lb | 5.90 kg |
For example, 13 stone 9 pounds is 82.55 + 4.08, which makes 86.63 kg. Using the two tables together, you can find any weight without doing a single multiplication.
Is 10.5 stone the same as 10 stone 5?
No. 10.5 stone means ten and a half stone, which is 10 stone 7 pounds, or 66.68 kg. Ten stone 5 pounds is lighter, at 65.77 kg.
The mix-up happens because a stone has 14 pounds, not 10. The figure after a decimal point is a share of a stone, not a count of pounds. Almost a full kilogram separates those two weights, which is enough to matter on a medical form.
If someone tells you their weight as “ten five” or “10-5”, they nearly always mean 10 stone 5 pounds. If a screen shows 10.5 st, it means ten and a half. When you are unsure, ask.
Can you work it out in your head?
Yes. Multiply the stone by 6, then add a third of the stone figure. The answer lands within a few hundred grams.
Take 12 stone. Twelve times 6 is 72. A third of 12 is 4. Add them and you get 76 kg. The exact answer is 76.2 kg.
Try 15 stone. Fifteen times 6 is 90. A third of 15 is 5. That makes 95 kg, against a true figure of 95.25 kg.
For spare pounds, count each one as roughly half a kilo. So 15 stone 4 is about 95 plus 2, or 97 kg. The exact answer is 97.07 kg. This is good enough for a conversation or a rough check, though not for anything official.
How much is a stone of weight loss in kg?
Losing one stone means losing 6.35 kg. Half a stone is 3.18 kg, and two stone is 12.7 kg.
Slimming groups in the UK often hand out awards at half-stone steps, so it helps to know what each step means in metric. Health advice, on the other hand, often talks about losing 5% of your body weight. For someone who weighs 15 stone, 5% is 10.5 pounds, which is 4.76 kg. Seeing both figures side by side makes it easier to follow a plan from your GP and a target from your group at the same time.
Why do doctors and gyms ask for your weight in kg?
Medicine and sport use kilograms because the sums they rely on are built on metric units. The NHS records patient weight in kilograms, and so do health services in most other countries.
There are a few everyday reasons you might need the metric figure:
- Medicine doses. Some medicines are prescribed by body weight, measured in milligrams per kilogram.
- Body mass index. The BMI formula uses kilograms and metres.
- Gym equipment. Weight plates, dumbbells and kettlebells in UK gyms are marked in kilograms.
- Travel. Airlines set baggage limits in kilograms, and some small aircraft ask for passenger weights too.
- Forms abroad. Outside the UK and Ireland, almost nobody knows what a stone is.
Knowing your weight both ways saves you from guessing at the desk.
How do you work out BMI from stone and pounds?
Change your weight to kilograms and your height to metres, then divide the weight by the height squared.
Say you weigh 12 stone and you are 5 feet 9 inches tall. Twelve stone is 76.2 kg. Five feet 9 inches is 1.75 metres. Multiply 1.75 by 1.75 and you get 3.0625. Divide 76.2 by 3.0625 and the answer is a BMI of 24.9.
For most adults, a BMI between 18.5 and 24.9 is counted as a healthy weight. BMI is only a rough guide. It does not tell muscle from fat, so a rugby player and an office worker can share a number and look nothing alike. Speak to your GP if your result worries you.
Is a stone the same weight in every country?
Yes, a stone is 14 pounds wherever it is used, but it is only used for body weight in the UK and Ireland. The pound itself is the same in Britain and America.
That means the pounds column in the table works for American readers. A person who weighs 12 stone in London weighs 168 pounds in New York and 76.2 kg in Paris. The body has not changed, only the unit.
Older books and records sometimes mention a stone of a different size, because local stones once ranged from 5 to 40 pounds depending on the goods being weighed. Those versions have long gone. Any stone you meet today is the 14-pound one.
What mistakes should you watch out for?
The biggest mistake is rounding 6.35 down to 6. It looks harmless, but it removes about a third of a kilogram for every stone.
At 15 stone, that shortcut gives 90 kg when the real figure is 95.25 kg. That is more than 5 kg out. Other slips to avoid:
- Forgetting the spare pounds and converting only the whole stone.
- Treating pounds as tenths, such as reading 9 stone 7 as 9.7.
- Multiplying pounds by 0.5. It is close, but it adds an extra kilogram for every 22 pounds.
- Mixing up the direction and dividing when you should multiply.
A quick check helps when you convert stone to kg. Your weight in kilograms should always be a bit more than six times your weight in stone.
Frequently asked questions
How many kg is 1 stone?
One stone is 6.35 kg. The exact figure is 6.35029318 kg.
What is half a stone in kg?
Half a stone is 3.18 kg, which is 7 pounds.
What is 9 stone in kg?
Nine stone is 57.15 kg, or 126 pounds.
What is 14 stone in kg?
Fourteen stone is 88.9 kg, or 196 pounds.
How do I convert stone to kg on a phone?
Open the calculator app. Type your stone, multiply by 14, add your spare pounds, then multiply by 0.453592. The number on screen is your weight in kilograms.
Is a stone heavier than a kilogram?
Yes. A stone is more than six times heavier than a kilogram.
How many stone is 100 kg?
100 kg is 15.75 stone, which is 15 stone 10.5 pounds.
Why is “lb” used for pounds?
It is short for libra, a Roman unit of weight. The word “pound” comes from the Latin phrase libra pondo, meaning “a pound by weight”.
What is the quickest way to remember all this?
Hold on to three numbers. One stone is 6.35 kg, one pound is 0.454 kg, and there are 14 pounds in a stone. With those, you can turn stone to kg on any calculator. When the answer needs to be exact, use the converter at the top of the page.