Question: what is the average head size of a 1 year old?
Answer: By his first birthday, the average child has tripled his birth weight and is 28 to 32 inches (71 to 81 cm) tall. Head growth between eight and twelve months slows down a bit from the first six months. Typical head size at eight months is 17 1⁄2 inches (44.5 cm) in circumference; by one year, it's 18 inches (46 cm).