Body Mass Index (BMI) Calculator

How the BMI Calculator Works

This body mass index calculator is based on the standard BMI measurement which is a correlation between your weight and height. BMI does not measure body fat i.e. the calculation cannot differentiate between those who are heavy because of excess fat OR excess muscle.

Since some muscle weighs more than fat a BMI calculation could give you a wrong reading. For an accurate picture of your body fat please also check out our Body Fat Percentage Calculator.

 

NOTE: If your BMI is not what you expect and you need to shed more weight then you should consider one of the fat loss programs here.

 

BMI Calculations

Metric Formula: weight (kg) / [height (m)]2
With the metric system, the formula for BMI is your weight in kilograms divided by your height in meters squared. Since your height is normally measured in centimeters, divide your height in centimeters by 100 to get the height in meters.

Example: Weight = 65 kg, Height = 160 cm (1.6 m)
BMI Calculation: 65 ÷ (1.6)2 = 25.39

 

Imperial Formula: weight (lb) / [height (in)]2 x 703
Calculate BMI by dividing your weight in pounds (lbs) by your height in inches (in) squared and multiplying by a conversion factor of 703.

Example: Weight = 143 lbs, Height = 5'3" (63")
BMI Calculation: [143 ÷ (63)2] x 703 = 25.33

 

With the final calculation you can then work out where you stand within the BMI scale, as seen below:

BMI	Weight Status
Below 18.5	Underweight
18.5 – 24.9	Normal
25.0 – 29.9	Overweight
30.0 and Above	Obese