For years, doctors have used height and weight measurements to
assess a child's physical growth in relation to other kids the
same age. Now they have another tool: body mass index (BMI). BMI
is a calculation that uses height and weight to estimate how
much body fat someone has. Doctors use it to determine how
appropriate a child's weight is for a certain height and age.
You can use the BMI calculator below to determine your child's
BMI, but it's also important to have your doctor perform regular
BMI measurements. That way, you'll know the number is accurate
and the doctor can discuss the results with you. Starting when
your child is 2 years old, the doctor will determine BMI at
routine checkups and plot this measurement on a chart against
those of other kids the same age. Because what is normal changes
with age, doctors must plot children's BMI measurements on
standard growth charts rather than using a universal normal
range for BMI as is done with adults. They also use separate
charts for boys and girls to a