While information on charts noting children's age and weight varies based on age of the child and source of the chart, they all include information regarding the average weight and length for age. Additional information that may appear on a chart is the percentile where a particular child's weight and height fall in comparison to other children his age, as well as body mass index.
The Center for Disease Control and Prevention has separate charts for infants from birth to 36 months, children and adolescents aged 2 to 20 years, and preschoolers aged 2 to 5 years. Length for age and weight for age are on the chart for infants, as are head circumference for age and weight for length. If children are able to stand at the age of 2, the chart for older children is to be used. If a child is unable to stand, length can be assessed on the birth to 36 months chart until the child reaches the age of 36 months. On the children and adolescents charts, there is information for stature for age and weight for age, as well as body mass index for age. The preschooler's chart shows weight for stature.
Charts are separated by sex to indicate differences that exist in average growth of boys versus girls.