How to Chart a BMI for an Age Percentile Growth Chart

The BMI age percentile growth chart is used by pediatricians, family doctors and other health care professionals to determine if a child or teen between the ages of 2 and 20 is overweight, obese or underweight. The BMI age percentile chart notifies doctors and parents if a child is gaining too much or not enough weight for his height and age and if your child has a clinical risk for hyperlipidemia, high blood pressure or high insulin levels.

Instructions

1

Measure your weight with a scale and your height with a tape measure. Calculate your weight in pounds and your height in inches.

2

Find your BMI value using the following equation: BMI = (weight / (height x height)) x 703. For example, if a child who is 13 years old weighs 80 lbs. and is 60 inches tall, his BMI would be calculated like this: (80 / (60 x 60)) x 703. The BMI is approximately 15.62.

3

Mark your BMI value onto a BMI scale (see Resources). Locate your BMI value on the right- and left-hand sides of the growth chart, and connect the two markings with a horizontal line through the chart.

4

Round your age to the nearest quarter year. Make a mark for the year on the bottom of the graph, and draw a vertical line through the chart.

5

Find the intersection of the horizontal and vertical lines. The cross point represents the BMI in terms of age. The BMI graph should show "J" curves that identity the percentiles 10th, 25th, 50th and so forth. If your BMI falls between two of the curves, your BMI percentile will be between the two numbers. For example, if a 19-year-old has a BMI of 22, his BMI for age percentile would fall between the 50th and 75th percentiles.