Average Head Circumference for a 11-Month-Old Girl
The average (50th-percentile) head circumference for a 11-month-old girl is 44.6 cm (17.6 in), based on the WHO Child Growth Standards. Across the healthy range, most girls this age have a head circumference between 42.0 cm (16.6 in) and 47.1 cm (18.6 in). (measured around the largest part of the head)
| Percentile | Metric | Imperial |
|---|---|---|
| 3rd | 42.0 cm | 16.6 in |
| 15th | 43.2 cm | 17.0 in |
| 50th | 44.6 cm | 17.6 in |
| 85th | 46.0 cm | 18.1 in |
| 97th | 47.1 cm | 18.6 in |
What's typical at this age
Head growth continues to ease — a few millimetres a month now. The anterior fontanelle (the diamond-shaped soft spot on top) is still open in most babies at this age. Between month 11 and month 12, the median girl's head circumference grows about 0.3 cm.
A percentile compares your girl to other girls the same age — the 50th is simply the middle. Being above or below it is usually completely normal; a baby who has always tracked the 15th or 85th percentile is typically growing exactly as they should. What pediatricians watch for is a sudden change in the pattern, not the number itself.
See your own baby's percentile
Enter your child's exact weight and height for their personal WHO percentile and growth curve.
Open the Growth Calculator →Percentiles calculated from the WHO Child Growth Standards (2006). For information only — not medical advice. If you're concerned about your child's growth, speak to your pediatrician or health visitor. Full disclaimer.