Head circumference percentiles for a 5-month-old girl

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 4 months to 5 months, the median rises by 0.9 cm. That is clearly less than in the month before, as growth gradually slows down. The gap between the 3rd and 97th percentile is 4.9 cm at this age, compared with 4.4 cm at birth, because the curves fan out as children grow. For comparison, the median for boys of the same age is 42.6 cm. Relative to their size, the gap between the girls' and boys' medians is larger now than at birth.

Head growth slows down steadily after the first months.

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.