The average height of a three-year-old male is between 36.5 and 38.6 inches, while the average height for a female is between 36 and 38.1 inches, according to BabyCenter. The average weight for a male of that age is 29.5 to 34.3 pounds, and a female is 28.4 to 33.4 pounds.
Half of all three-year-old children fit within these parameters, according to data collected from the Centers for Disease Control and Prevention, states BabyCenter. One quarter of all children fall below these numbers, and one quarter are above these numbers. Gender, heredity, nutrition and hormones all affect the growth of a child, explains Eli Lilly and Company.