Remarks Regarding BMI and CDC Percentile Descriptions Inconsistencies

There are several combinations of sex, age, height, weight, and BMI values that will result in inconsistent BMI and CDC Percentile descriptions. This is normal. These inconsistencies are common in the lower age ranges.

1.     BMI uses a well defined and established formula:

Metric: Weight in Kilograms / Height in Centimeters / Height in Centimeters * 10000

or

English: Weight in Pounds / Height in Inches / Height in Inches * 703

2.     CDC BMI values their descriptions are based on a series of percentile curves that illustrate the distribution of selected body measurements in children.

As an example:

Sex: Male

Age: 6 years old

Height: 48 inches

Weight: 60 pounds

Results in:

BMI Description: Underweight

CDC BMI Description: Obese 

References:
http://www.cdc.gov/growthcharts/who_charts.htm
http://www.cdc.gov/growthcharts/percentile_data_files.htm