For adults, overweight and obesity ranges are measured by using
weight and height to compute the person’s BMI. The BMI is used
because, for most people, it correlates with the amount of fat in
their bodies.
Children grow at different rates at different times, so it is not
always easy to tell if a child is overweight. BMI charts for children
compare their height and weight to other children of their same
sex and age.
The tables to the right outline BMI scores and weight categories for
adults and children. Online tools for gauging the BMIs of children
and adults are listed in the Resources section of this fact sheet.