According to KidsHealth, the average 4-year-old is 40 inches tall and weighs 40 pounds. Children usually gain 4 to 5 pounds during their fourth year and add 2 to 3 inches in height.
MedlinePlus lists a number of physical milestones that most 4-year-olds achieve. For example, their height is double their birth length. Most have stopped napping but sleep 11 to 13 hours at night. Bed wetting is still normal at this age.
Four-year-olds have good coordination, Medline Plus notes. They are able to balance while hopping on one foot, and they throw a ball overhand. Fine motor skills are improving as well, so children use scissors effectively.