BMI Percentile Calculator

A child's BMI means very little against the adult cut-offs, because BMI changes shape steeply through childhood, so it is read against other children of the same sex and age instead. Enter the sex, the age in years and months, the height and the weight, and this returns the BMI, its percentile on the CDC 2000 BMI-for-age reference, the z-score and the CDC weight status category, along with the BMI that would sit on the 5th, 85th and 95th percentile lines at that age. The reference runs from 24 months to the twentieth birthday, and the published LMS parameters are used unchanged and checked against the percentile columns printed in the same data file. This is an estimate rather than a diagnosis, and a single reading matters far less than the trend over time, so take any concern to the child's doctor.