Question: how much should the average 13 year old boy weigh?
Answer: Average weight of a 13-year-old boy The weight range for 13-year-old boys is between 75 and 145 pounds. Weights in the 50th percentile for this age land at 100 pounds. If a child falls into the 50th percentile for weight, this means that of 100 kids his age, 50 will weigh more while another 50 will weigh less.