Baby Center offers an online size and growth timeline chart for children from birth through 8 years of age. The chart is based on the 25th to 75th percentiles for weight and height, so half of all children fall within the suggested ranges on the chart.
Because the chart is based on the weights and heights of the majority of children within each age group, it is only useful as a benchmark, notes Baby Center. The chart is divided by age group and gender. For example, it lists the average weight for a baby boy at birth as 6.7 to 8.1 pounds, while the average weight of a baby girl is listed at 6.5 to 7.8 pounds.