Content

• To step
• Method 1 of 2: Method 1: Using a formula
• Method 2 of 2: Method 2: Mental arithmetic
• Tips
• Warnings

There are many calculators on the internet where you can convert quantities in International Pounds (lb) to kilograms (kg), but it is useful to be able to do it yourself. One of the simplest ways is to divide the number in pounds by 2.2, which will give you approximately the correct answer. This article shows the mathematical steps to convert from pounds to kilograms.

To step

Method 1 of 2: Method 1: Using a formula

1. Put a value in pounds that you want to convert in the empty space below. This is shown in the formula as "lb". You use this formula to determine the quantity in kilograms. One kilogram equals 2.2046226218 (that's abbreviated to 2.2 from here)

   • ____ lb

     *

     1 kg 2.2046226218 lb

     =

     ? kg

2. Make the calculation to get the result in kilograms. First you divide 1 kg by 2.2 lbs, and then you multiply that number by the value in pounds you want to convert.
   • Example: Suppose you want to convert 4 pounds to kilograms. Then you first divide 1 kg by 2.2 lbs, which is 0.45. Then you multiply 0.45 by 4, which is 1.81. So 4 lb equals 1.81 kg.

Method 2 of 2: Method 2: Mental arithmetic

1. Subtract the first digit of the weight in pounds from the total number and divide by two.
   • Example: Convert 46 lbs to kg. Subtract 4 from 46, which is 42. Divide 42 by 2, which is 21 (Using the formula you get 20.87 kg, but that can be rounded to 21).

Tips

• Divide the weight in pounds by 2.2. That gives you an approximate weight in kilograms. The most reliable method is to use the formula above, or an online calculator, if you want to know the exact answer.
• If you are doing a math homework assignment, make sure you can show the entire process and use the first method.

Warnings

• The main calculation method is only suitable if you only need an estimate of the quantity.