How to Gauge BMI for Children

Body mass index (BMI) is a mathematical calculation used to screen children for weight-related health problems by estimating their percentage of body fat and comparing their height and weight measurements with that of other children of the same age and sex. Child BMIs take into account the distinct growth patterns of males and females as they vary with age. Children's BMIs are interpreted in percentiles on the Centers for Disease Control and Prevention's BMI-for-age growth charts. Less than 5th percentile is classified as underweight, healthy weight is 5th to 85th, overweight is 85th to 94th and obese is 95th percentile and above.

Things You'll Need

• Measuring tape
• Scale
• Scratch paper and pencil or calculator
• BMI chart

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Instructions

• 1

  Obtain an accurate height and weight for the child.

• 2

  Use the BMI formula, or an online BMI calculator (see resources below), to determine the BMI. To manually calculate BMI, multiply height in inches by height in inches. Divide the weight in pounds by the number achieved by multiplying the height. Multiply that number by 703.

• 3

  Plot the BMI on a BMI chart (see resources below) to determine if the BMI is classified in the underweight, healthy weight, overweight or obese percentile.

• 4

  Talk to your doctor is you have any concerns about your child's BMI. Only a physician can accurately tell you if you should be concerned about your child's weight and what you can do to ensure that your child is healthy.