Toddlers at 3 years of age are very active and are continually growing. According to Kids Health, the average 3-year-old gains approximately four pounds and grows two to three inches taller in a single year.
At the age of 3, there is a slight difference between boys and girls in regards to size. Though they both are about the same height, on average, girls tend to weigh a little bit less than boys at this age.
The average, and healthy height, for 3-year-old boys and girls is 2 feet, 9 inches.
At the age of 3, boys weigh a little bit more than girls, averaging 15 Kilogram. Girls at this age are a few pounds less, at an average weight of 14 Kilogram.