To determine whether a child is growing at a healthy pace in both height and weight, many pediatricians and child care providers consult widely available growth charts for comparison with other children. These charts reveal a range of normal heights and weights for both boys and girls. Three-year-old girls range from 35 to 40 inches in height and 25.5 to 38.5 pounds in weight. For boys, the range is 35.5 to 40.5 inches in height and 27 to 38.5 pounds in weight.
All children grow at different rates. Growth rates depend on many individual aspects of a child's life including both genetic and environmental factors. To help determine whether a child is growing at an average rate in both height and weight, pediatricians refer to growth charts that graph a range of heights and weights for children at a particular age. This information informs the pediatrician how a child compares to other kids her age.
Home On the Range
Using growth charts, it is easy to see that the normal height and weight ranges for 3-year-old girls and boys are similar. Girls range from 35 to 40 inches in height, and boys are on average a half inch taller. Girls have a weight range of 25.5 to 38.5 pounds and boys range from 27 to 38.5 pounds. These ranges are quite wide, however, and it is difficult to determine whether a child is growing at a normal rate by looking only at a single point in time.
A Curious Curve
To accurately measure whether a 3-year-old is growing appropriately, you can plot her monthly height and weight for the year leading up to three years. A normally growing child will typically follow the curves of the height-weight chart, though during spurts and lulls her height and weight might jump on the chart slightly. Large drops in either height or weight growth can be alarming, however, and you should discuss them with your pediatrician.
What is Normal?
After comparing a child's height and weight to what is called normal on a height and weight chart, many people are tempted to say a child is not normal. As long as a child is growing at a regular rate, his position in the height and weight range is not important. Measurements falling anywhere in the ranges is considered normal, as long as rates are regular.
In addition to height and weight charts, pediatricians and parents may also use the Body Mass Index (BMI) range chart for both boys and girls. BMI is a calculation that incorporates both a child's height and weight into one measurement. According to the Centers for Disease Control's measurements for the year 2000, the normal BMI range for a three-year-old girl is 14 to 18.2, and for boys the range is 14.4 to 18.2.