Airline baggage limits in kilograms, a gym that labels plates in pounds, a doctor's scale in one and a fitness app in the other — kg and lb are constantly mixed up. Here's how to switch between them quickly and accurately.
The exact conversion
- 1 kilogram = 2.20462 pounds
- 1 pound = 0.453592 kilograms
So:
- kg to lb: multiply by 2.20462
- lb to kg: multiply by 0.453592 (or divide by 2.20462)
Worked examples
- 70 kg to lb: 70 × 2.20462 = 154.3 lb
- 180 lb to kg: 180 × 0.453592 = 81.6 kg
- 23 kg to lb: 23 × 2.20462 = 50.7 lb
The quick mental trick
kg to lb: double it, then add 10%. 70 kg → 140 + 14 = 154 lb. Very close to the exact 154.3.
lb to kg: halve it, then subtract 10%. 180 lb → 90 − 9 = 81 kg. The exact answer is 81.6.
Good enough for the gym or the check-in desk; use the exact figure for medicine or shipping.
Body weight chart
| Kilograms | Pounds |
|---|---|
| 50 kg | 110.2 lb |
| 60 kg | 132.3 lb |
| 70 kg | 154.3 lb |
| 80 kg | 176.4 lb |
| 90 kg | 198.4 lb |
| 100 kg | 220.5 lb |
Luggage limits
Many airlines set checked bags at 23 kg, often written as 50 lb — 23 kg is really 50.7 lb, so the two are treated as equivalent. Carry-on limits are commonly 7–10 kg (15–22 lb), but always check your airline.
Gym weights
Plates come in either system, and they're not the same:
- A 20 kg plate is 44.1 lb; a 45 lb plate is 20.4 kg.
- A standard Olympic bar is 20 kg (44 lb); US bars are often labelled 45 lb.
If your program is written in one unit and your gym uses the other, convert your working weights once and write them down.
Ounces and grams
For smaller amounts:
- 1 lb = 16 oz
- 1 oz = 28.35 g
- 100 g = 3.53 oz
What about stone?
In the UK, body weight is often given in stone. 1 stone = 14 lb = 6.35 kg. To convert, turn stone into pounds first (× 14), then pounds into kilograms.
Convert instantly
- Open the free Unit Converter.
- Choose Weight.
- Pick kilograms, pounds, grams, ounces, milligrams or metric tons, and type a value.
FAQ
Is a pound exactly 0.453592 kg? It's defined as exactly 0.45359237 kg.
Does converting change my BMI? No — BMI is the same whichever units you use. See How to Calculate and Understand Your BMI.
Try it now
Convert weights with the free Unit Converter.
Related reading
See How to Convert Celsius to Fahrenheit and Everyday Unit Conversions Made Simple.