Body Mass Index (BMI) and weight calculation for children and teens, between the ages of 2 and 19 years.

Body Mass Index or BMI is a useful tool to assess a child's weight status, using height and weight to determine the amount of body fat. Use BMI Calculator below to determine if a child is underweight, at a healthy (normal) weight, overweight or obese.

For adults, 20 years old and older, use BMI Calculator for Adults.
Measurement Date:


Choose to use "Birth Date" or "Age" to calculate.
Birth Date:


Age: (2-19 years age range)


Choose Unit:
Input Height:

Input Weight:

BMI-for-Age Percentile and Weight Status:
Underweight Percentile Range: less than 5th
Normal Percentile Range: 5th to less than 85th
Overweight Percentile Range: 85th to less than 95th
Obese Percentile Range: 95th or greater
Calculated Percentile:
Calculated BMI:


BMI is used differently for children and teens. Although it is calculated the same way as for adults, interpreting Body Mass Index (BMI) for children and teens is a bit more complicated. For children and teens, the amount of body fat changes with age and differs between boys and girls. The BMI-for-age percentile is used in interpreting BMI which considers both age and gender for children and teens.

BMI is a measure of body fatness based on a child's height and weight. BMI is an easy method to screen for healthy body weight based on a child's height. When using kilograms and meters for weight and height, BMI is calculated by dividing the weight (W) by the squared height (H): BMI=W/. When using pounds and inches for weight and height, the formula to calculate BMI is: BMI=(W/) x 703.

The BMI-for-age percentile shows how a child's weight compares to that of other children and teens of the same age and gender. The BMI-for-age percentile and weight categories are: underweight (percentile range: less than 5th), normal or healthy weight (percentile range: 5th to less than 85th), overweight (percentile range: 85th to less than 95th), and obese (percentile range: 95th or greater).
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