Baby head circumference
Depending on age and gender a baby's average head size can vary greatly! 50th percentile (average) at birth is 14.25 inchesfor boys, and 13.75 inches for girls. For the first 6 months a baby's head should grow about 1/2" per month. Then 1/4" per month from 6-12months. By a year the average head circumference is around 20in.