The short answer
- One pound is exactly 0.45359237 kg.
- One stone is 14 pounds, or 6.35 kg.
- One kilogram is about 2.2 pounds.
- One pound is 16 ounces.
Stones, pounds and kilograms
The kilogram is the metric unit used by science, medicine and nearly every country. The pound is an imperial unit still used for body weight in the UK and US. Since 1959, the UK, US and other English-speaking countries have defined the pound as exactly 0.45359237 kg, and UK law sets this out in the Weights and Measures Act 1985.
The stone, 14 pounds, is used almost only in the UK and Ireland, and almost only for body weight. Americans give their weight in pounds alone: a person who is 11 stone in the UK is 154 lb in the US.
Stones to kilograms
- Stones to pounds11 × 14154 lb
- Add the extra pounds154 + 4158 lb
- Pounds to kilograms158 × 0.4535923771.67 kg
Kilograms to stones
- Kilograms to pounds70 ÷ 0.45359237154.3 lb
- Whole stones154.3 ÷ 14 = 11.0211 st
- Pounds left over154.3 − 11 × 140.3 lb
A quick mental check: a stone is a little over 6 kg, so divide kilograms by about 6.35. 100 kg is 15 st 10.5 lb, just under 16 stone.
Stone to kg table
| Stones | Kilograms | Pounds |
|---|---|---|
| 7 st | 44.5 | 98 |
| 8 st | 50.8 | 112 |
| 9 st | 57.2 | 126 |
| 10 st | 63.5 | 140 |
| 11 st | 69.9 | 154 |
| 12 st | 76.2 | 168 |
| 13 st | 82.6 | 182 |
| 14 st | 88.9 | 196 |
| 15 st | 95.3 | 210 |
| 16 st | 101.6 | 224 |
| 17 st | 108.0 | 238 |
| 18 st | 114.3 | 252 |
| 19 st | 120.7 | 266 |
| 20 st | 127.0 | 280 |
| 21 st | 133.4 | 294 |
| 22 st | 139.7 | 308 |
| 23 st | 146.1 | 322 |
| 24 st | 152.4 | 336 |
| 25 st | 158.8 | 350 |
| Kilograms | Stones and pounds | Pounds |
|---|---|---|
| 50 kg | 7 st 12.2 lb | 110.2 |
| 60 kg | 9 st 6.3 lb | 132.3 |
| 70 kg | 11 st 0.3 lb | 154.3 |
| 80 kg | 12 st 8.4 lb | 176.4 |
| 90 kg | 14 st 2.4 lb | 198.4 |
| 100 kg | 15 st 10.5 lb | 220.5 |
Decimal stones versus stones and pounds
Stones are not decimal. 11.5 stone means eleven and a half stone, which is 11 st 7 lb, not 11 st 5 lb. Some scales and apps show decimal stones, so the same weight of 70 kg can appear as 11.02 st or as 11 st 0.3 lb. The calculator shows stones and pounds by default; switch to decimal stones under More options.
Rounding
Choose 0, 1 or 2 decimal places. When the pounds round up to 14, the calculator carries them into the next stone, so you never see "10 st 14 lb".
Baby weights in pounds and ounces
UK hospitals weigh babies in kilograms and record them in the red book (personal child health record), but many families still share birth weights in pounds and ounces. To convert, turn kilograms into pounds, then multiply the fraction of a pound by 16.
| Kilograms | Pounds and ounces |
|---|---|
| 2.5 kg | 5 lb 8 oz |
| 3.4 kg | 7 lb 8 oz |
| 4.0 kg | 8 lb 13 oz |
Luggage allowances
Airlines set baggage limits in kilograms, and sometimes also in pounds. Allowances vary by airline and fare, so always check yours. Common figures convert as follows:
| Kilograms | Pounds | Stones and pounds |
|---|---|---|
| 7 kg | 15.4 | 1 st 1.4 lb |
| 10 kg | 22.0 | 1 st 8 lb |
| 20 kg | 44.1 | 3 st 2.1 lb |
| 23 kg | 50.7 | 3 st 8.7 lb |
| 32 kg | 70.5 | 5 st 0.5 lb |
Weight and health
Weight on its own says little about health without your height. Use our BMI calculator to check your weight against the healthy range, the calorie calculator to plan a steady change, and the feet to cm converter if your height is in different units.