Body Mass Index is defined as weight in kilos divided by height, squared..so it looks like this: kg/m2

Body mass index (BMI) is measure of body fat based on height and weight that applies to both adult men and women.

BMI Categories:

Normal weight = 18.5-24.9

Overweight = 25-29.9

Obesity = BMI of 30 or greater

Reference: US Department of Health and Human Services, retrieved from:  http://www.nhlbisupport.com/bmi/bminojs.htm

The information you need is someone's weight in kilograms and then their height.  The formula is:

 Metric BMI Formula BMI = ( Weight in Kilograms / ( Height in Meters ) x ( Height in Meters ) )

For example:   BMI = (75 kg/ 1.6 m) x (1.6 m) = 75/2.56 =29.29 BMI, which then rounds up to 29.3…This BMI indicates this person is overweight…not quite obese, but getting close!

Exercise: Calculate your own BMI, where are you on the  BMI scale?