BMI Calculator

BMI Chart
Ages 2-19
Under Weight <18.5 <5th
Normal Weight 18.5−<25 5th−<85th
Overweight 25−<30 85th−<95th
Obese (Class I) 30−<35 >=95th
Obese (Class II) 35−< 40 >=120%−<140%
of the 95th
Obese (Class III+) >=40 >=140%
of the 95th

Health professionals use a BMI Calculator to determine if you are at a healthy weight for your age and height. You can enter some basic information about yourself into Pennington Biomedical’s BMI Calculator to learn the following:


BMI (Body Mass Index) is an estimate of body fat and is calculated for both children and adults. A high BMI might mean you are at a higher risk for diseases associated with obesity.

BMI Percentile

The BMI Percentile is calculated for children and young adults aged 2 to 19.  Health professionals can use the percentile score to categorize a child’s BMI to identify where the child falls in relation to other children of the same age and sex.


BMI Z-Scores are also calculated for children and young adults aged 2 to 19. This number indicates how much higher or lower your BMI is on a standard growth chart. BMI Z-Scores help health professionals to monitor weight changes in children and adolescents especially if they are in the underweight or overweight percentiles.