Head circumference percentiles for a 4-year-old boy

Percentile table

Values from the WHO table, rounded to one decimal.

Source: WHO Child Growth Standards, head circumference-for-age table. Every value on this page is checked automatically against the published WHO table before publishing, and the calculator uses WHO's LMS method. Updated October 2, 2026. Corrections and questions: ahozon@benbasha.com

How growth looks at this age

From 47 months to 48 months, the median rises by 0.05 cm. That is a little less than in the month before. Over the last 12 months the median rose by 0.8 cm. The gap between the 3rd and 97th percentile is 5.5 cm at this age, compared with 4.8 cm at birth, because the curves fan out as children grow. For comparison, the median for girls of the same age is 49.3 cm. Relative to their size, the gap between the girls' and boys' medians is about the same as at birth.

After the second birthday head circumference changes slowly, and the yearly change is small compared with the first year.

What does the percentile mean?

A percentile compares a child with healthy children of the same age and sex from the WHO Multicentre Growth Reference Study. At the 40th percentile, 40 out of 100 children have a smaller head circumference and 60 a larger one. Anything between the 3rd and 97th percentile is in the normal range. What matters most is that a child keeps following a similar curve over time.

How to measure

Measure with a flexible tape around the widest part of the head, just above the eyebrows and ears. Take the largest of three readings.

When to ask your pediatrician

Talk to your pediatrician or child health nurse if a measurement is below the 3rd or above the 97th percentile, or if your child's percentile changes a lot between visits, for example crossing two of the main percentile lines. A single measurement says little; the trend over time matters most.