What is a pounds to kilograms converter?
A pounds to kilograms converter is an online tool that turns a weight given in pounds (lb), an imperial and US customary unit, into kilograms (kg), the base unit of mass in the metric system. It works both ways, so you can also convert kilograms back into pounds whenever you need to.
Pounds are widely used in the United States for body weight, food, shipping and countless everyday measurements. Kilograms are the standard almost everywhere else and throughout science, medicine and international trade. Being able to move between the two makes it easy to follow a recipe from another country, read a fitness plan, interpret luggage limits or check a shipping weight.
How does it work?
The conversion is based on a single exact relationship: one pound equals exactly 0.45359237 kilograms. To convert pounds to kilograms you multiply by this factor, and to convert kilograms to pounds you divide by it.
Because the factor is defined exactly, the conversion is as precise as you want it to be; any small differences you notice are only the result of rounding the answer for display.
Formula
To convert pounds to kilograms, multiply the weight in pounds by 0.45359237:
To convert kilograms to pounds, divide by the same factor (equivalently, multiply by about 2.20462):
Example conversions
Convert 10 pounds to kilograms
So 10 pounds is approximately 4.536 kilograms.
Convert 1 kilogram to pounds
One kilogram is therefore about 2.205 pounds.
Conversion table
| Pounds (lb) | Kilograms (kg) |
|---|---|
| 1 | 0.4536 |
| 5 | 2.2680 |
| 10 | 4.5359 |
| 25 | 11.3398 |
| 50 | 22.6796 |
| 100 | 45.3592 |
| 150 | 68.0389 |
Notes
- For quick mental estimates, remember that 1 pound is roughly 0.45 kg, and 1 kilogram is a little over 2.2 pounds.
- The pound used here is the international avoirdupois pound, the standard for everyday weight. The troy pound used for precious metals is different and should not be converted with this tool.
- If you weigh yourself in stones and pounds, our stone to pounds converter can help before you convert to kilograms.
Frequently asked questions
How many kilograms are in a pound?
There are exactly 0.45359237 kilograms in one pound, commonly rounded to 0.4536 kg.
How do I convert pounds to kilograms quickly?
Multiply the number of pounds by about 0.45. For a rough figure, halving the pounds and subtracting a little gives a usable estimate.
How many pounds are in a kilogram?
One kilogram is about 2.20462 pounds, so a value in kilograms is a bit more than double the same number of pounds.
Why is one pound exactly 0.45359237 kg?
Since 1959 the international avoirdupois pound has been defined by international agreement as exactly 0.45359237 kilograms, which is why the factor can be written out precisely.