Kilograms to Stone
Quick answer: 1 kg = 0.15747 st. To convert, multiply the kg value by 0.15747; to go back, divide.
Body weight in the UK and Ireland is still spoken in stone and pounds ("11 stone 4"), while scales, doctors and gyms read kilograms. One stone is 14 pounds = 6.35029 kg, so divide kilograms by 6.35029318 to get stone; multiply the fraction by 14 for the pounds.
The formula
st = kg ÷ 6.35029318 · kg = st × 6.35029318
Common values
| kg | st | also |
|---|---|---|
| 2.5 kg | 0.394 st | 0 st 5.5 lb |
| 4.5 kg | 0.709 st | 0 st 9.9 lb |
| 10 kg | 1.575 st | 1 st 8 lb |
| 20 kg | 3.149 st | 3 st 2.1 lb |
| 40 kg | 6.299 st | 6 st 4.2 lb |
| 50 kg | 7.874 st | 7 st 12.2 lb |
| 60 kg | 9.448 st | 9 st 6.3 lb |
| 65 kg | 10.236 st | 10 st 3.3 lb |
| 70 kg | 11.023 st | 11 st 0.3 lb |
| 75 kg | 11.81 st | 11 st 11.3 lb |
| 80 kg | 12.598 st | 12 st 8.4 lb |
| 85 kg | 13.385 st | 13 st 5.4 lb |
| 90 kg | 14.173 st | 14 st 2.4 lb |
| 100 kg | 15.747 st | 15 st 10.5 lb |
| 120 kg | 18.897 st | 18 st 12.6 lb |
2.5 kg to st: 0.394 st
2.5 kg = 0.394 st — 0 st 5.5 lb. Working: 2.5 × 0.15747 = 0.3937.
Using the full factor, 2.5 ÷ 6.35029318 = 0.3936826… st. It is less than one stone, so the mixed-unit answer is 0 st 5.51 lb to two decimal pounds. Multiplying the decimal stone by 14 gives the total pounds: about 5.5116 lb.
4.5 kg to st: 0.709 st
4.5 kg = 0.709 st — 0 st 9.9 lb. Working: 4.5 × 0.15747 = 0.7086.
4.5 ÷ 6.35029318 = 0.7086287… st, or about 9.9208 lb. In stone and pounds this is 0 st 9.92 lb. Rounding it to 10 lb is convenient for an estimate, but it is not an exact equivalence.
The other way: st to kg
| st | kg |
|---|---|
| 1 st | 6.35 kg |
| 2 st | 12.701 kg |
| 5 st | 31.751 kg |
| 10 st | 63.503 kg |
| 12 st | 76.204 kg |
| 15 st | 95.254 kg |
| 20 st | 127.006 kg |
| 25 st | 158.757 kg |
| 50 st | 317.515 kg |
| 100 st | 635.029 kg |
Common mistake
Reading the decimal as pounds: 13.39 st is not 13 st 39 lb. Multiply the fraction by 14 — 0.39 × 14 = 5.5 lb.
Where the factor comes from
A stone is defined as exactly 14 pounds, and a pound has been exactly 0.45359237 kg since the 1959 international agreement. So one stone is 14 × 0.45359237 = 6.35029318 kg exactly, and one kilogram is 1 ÷ 6.35029318 ≈ 0.157473 stone.
The definition of 6.35029318 kg per stone is exact. Its reciprocal has more digits than the 0.157473 shown here, so that displayed multiplier is rounded. The calculator uses division by the full defined factor.
Stones and pounds, not decimal stone
This is the part that trips people up, and it matters because decimal stone and stone-and-pounds notation mean different things.
A calculator gives decimal stone. British usage is stones and pounds, so the decimal has to be converted — and there are 14 pounds in a stone, not 10 and not 16.
- Divide kilograms by 6.35029318 for decimal stone. For 70 kg: 70 ÷ 6.35029318 = 11.023 st.
- Keep the whole number: 11 st.
- Multiply the remainder by 14: 0.023 × 14 = 0.3 lb.
- 70 kg is 11 st 0.3 lb — essentially 11 stone dead.
Reading 11.02 st as "11 stone 2 pounds" is wrong: 11 st 2 lb is 70.8 kg, nearly a kilogram heavier.
Body weight conversion table
The overwhelmingly common reason to convert kilograms to stone is body weight, usually because a scale reads in one unit and a doctor, gym or family member uses the other.
| kg | Decimal stone | Stones and pounds | Pounds |
|---|---|---|---|
| 50 kg | 7.87 st | 7 st 12.2 lb | 110.2 lb |
| 55 kg | 8.66 st | 8 st 9.3 lb | 121.3 lb |
| 60 kg | 9.45 st | 9 st 6.3 lb | 132.3 lb |
| 65 kg | 10.24 st | 10 st 3.3 lb | 143.3 lb |
| 70 kg | 11.02 st | 11 st 0.3 lb | 154.3 lb |
| 75 kg | 11.81 st | 11 st 11.3 lb | 165.3 lb |
| 80 kg | 12.60 st | 12 st 8.4 lb | 176.4 lb |
| 85 kg | 13.39 st | 13 st 5.4 lb | 187.4 lb |
| 90 kg | 14.17 st | 14 st 2.4 lb | 198.4 lb |
| 95 kg | 14.96 st | 14 st 13.4 lb | 209.4 lb |
| 100 kg | 15.75 st | 15 st 10.5 lb | 220.5 lb |
| 110 kg | 17.32 st | 17 st 4.5 lb | 242.5 lb |
| 120 kg | 18.90 st | 18 st 12.6 lb | 264.6 lb |
A useful anchor: 10 stone is 63.5 kg and 1 stone is about 6.35 kg, so each stone up or down is roughly six and a third kilos.
Small weights in stone
For small masses, the whole-stone part is zero. This is expected: 2.5 kg is about 0.394 st, or 0 st 5.51 lb. Use the decimal-stone result if a form asks for a single number, or the mixed result if it has separate stone and pound fields.
Estimating in your head
- Divide by 6. 70 kg → about 11.7 st. Quick, roughly 6% high.
- Divide by 6, then take off 5%. 70 kg → 11.7 − 0.6 = 11.1 st. Within 1% of the true 11.02.
- Halve it, then divide by 3. 70 → 35 → 11.7 st. Same as the first, sometimes easier.
For pounds instead, doubling and adding 10% is very close: 70 kg → 140 + 14 = 154 lb, against a true 154.3 lb.
Related conversions: our weight conversion guide covers every unit with its exact factor, and kilograms to pounds handles the conversion most people need alongside stone.
Frequently asked questions
Is the conversion exact?
Yes — the factor follows from the legal definition of the units (1 lb = 0.45359237 kg and 1 st = 14 lb), so the only rounding is in the last decimal place shown.
How do I convert a different value?
Use the kg to st converter for any number, or the weight conversion guide for every weight unit and formula in one place.
How many stone is 70 kg?
11.02 stone, which in stones and pounds is 11 st 0.3 lb — essentially 11 stone. Divide kilograms by 6.35029318 for decimal stone, then multiply the remainder by 14 for pounds.
How many kg is 10 stone?
63.5 kg. One stone is 6.35029318 kg exactly, so ten stone is exactly 63.5029318 kg, or 63.5029 kg rounded to four decimals.
Why does my answer say 11.02 stone and not 11 stone 2 pounds?
Because 11.02 is decimal stone, and there are 14 pounds in a stone rather than 10 or 100. Multiply the 0.02 by 14 to get 0.3 lb. 11 st 2 lb would be 70.8 kg.
Conversion reference and rounding
The NIST conversion-factor reference lists the defined inch, international foot and avoirdupois pound. The calculator divides by the full factor and rounds only the displayed result. Table entries are rounded approximations; converting a measurement does not increase its original precision.
Comments