Head Circumference for Boys, Birth to 36 Months
Find your child's growth percentile based on age and height.
For children under 2, the CDC now recommends the World Health Organization (WHO) growth standards. This chart is the CDC's earlier version. Ask your child's doctor which chart they use, or see the WHO-based charts from the CDC.
This chart shows the head circumference percentiles for boys from birth to 36 months.
How to read the chart
The curved lines show head circumference percentiles. For example, the top curved line shows the 95th percentile, which means that 95% of boys are at or under that value.
The bottom of the chart shows ages, from birth to 36 months. The left and right sides of the chart show head circumference measurements.
The chart shows that at birth 95% of boys have a head circumference less than 16 inches (about 39 centimeters) and 5% are less than 12.5 inches (32 cm). At 36 months (3 years) 95% of boys are less than 21.75 inches (about 53 cm) and about 5% are less than 18.5 inches (47 cm).
Find your child's head circumference on either side, and read horizontally across until you reach the vertical line for your child's age. Then see where that point is among the percentile lines.
For example, a boy with a head circumference of 19 inches (48 cm) tall and 21 months old is just below the 50th percentile.
Consult your doctor if you are concerned about your child's growth.
About this chart
The chart comes from the Centers for Disease Control and Prevention's National Center for Health Statistics. We converted it from the CDC's PDF into a web image. Print the PDF version if you'd like to record your child's measurements.