Pounds to Kilograms Calculator
Convert a weight in pounds (lb) to kilograms (kg). Enter a value in pounds and the calculator returns the equivalent in kilograms using the exact international definition of the pound.
How It Works
Since 1959, the international avoirdupois pound has been defined as exactly 0.45359237 kilograms, so this conversion is precise rather than approximate. Multiplying the number of pounds by that factor gives the mass in kilograms. Because most of the world records weight in kilograms, this direction matters when you need to translate a US figure into the metric units expected on official forms. A common rounding is 0.4536, which stays accurate to well under a gram for typical weights.
Worked Examples
Example 1 — adult weight. 150 lb × 0.45359237 ≈ 68.04 kg.
Example 2 — checked luggage. A 50 lb bag × 0.45359237 ≈ 22.68 kg, just over a common 23 kg airline limit.
When to Use This Calculator
Reach for this conversion when an international medical, immigration, or travel form asks for weight in kilograms, when you ship a parcel to a country that prices by metric weight, or when you compare your luggage against an airline allowance that is published in kilograms. It also helps when adapting strength-training programs written for metric plates.
| Pounds | Kilograms |
|---|---|
| 1 lb | 0.45 kg |
| 10 lb | 4.54 kg |
| 25 lb | 11.34 kg |
| 50 lb | 22.68 kg |
| 100 lb | 45.36 kg |
| 150 lb | 68.04 kg |
| 200 lb | 90.72 kg |
Frequently Asked Questions
How many kilograms is 1 pound?
One pound equals exactly 0.45359237 kilograms, which is usually rounded to 0.454 kg for everyday use.
What is a fast way to estimate pounds in kilograms?
Divide the pounds by 2.2. For example, 150 lb divided by 2.2 is about 68 kg, which matches the exact answer closely.
Why do airlines list baggage limits in kilograms?
Most countries outside the United States use the metric system, so international carriers publish allowances such as 23 kg or 32 kg; converting your bag from pounds tells you whether it qualifies.