How To: Convert American Pounds to Kilograms

In this video, learn how to convert the American pound (lb.), a United States customary unit of mass, into kilograms (kg), a metric unit of mass in the International System of Units (SI).

First, the equation for converting weight from pounds (lbs.) to kilograms is 1 pound divided by 2.2, since every kilogram equals 2.2 lbs. For example, 40 lbs. divided by 2.2 will equal about 18.182 kg, or 18.2 kg rounded up.

Now, if you want to calculate 25 milligrams (mg) per kilogram dose, you must divide the pounds by 2.2. For 40 lbs, let's go with 18.2 kg. Then, multiply that by 25 to get 455 mg per kg dose.

Applying the above equation to convert the pound into a kilogram is very simple. To convert kilograms to pounds, just do the opposite and multiply kilograms by 2.2. For example, 56 kg x 2.2 would be 123.2 lbs.