Normal range for babies and toddlers
For children up to 36 months, the normal range is usually taken as roughly the 3rd to the 97th percentile of the growth charts. For boys and girls together, that is about 31.5 to 37 cm at birth, 42 to 48.5 cm at 12 months and 44.5 to 51 cm at 24 months.
Normal range for children and adults
After age three, head growth slows. A typical 8-year-old head is about 52.5 cm, still 4 to 5 cm short of adult size. Adult men typically measure 55 to 60.5 cm and women 53 to 59.5 cm.
| Age | cm | Inches | US |
|---|---|---|---|
| Preemie | 25 – 32 | 9.8 – 12.6 | – |
| Newborn | 32 – 36 | 12.6 – 14.2 | – |
| 0 to 3 months | 35 – 40.5 | 13.8 – 15.9 | – |
| 3 to 6 months | 39.5 – 43.5 | 15.6 – 17.1 | – |
| 6 to 12 months | 42 – 47 | 16.5 – 18.5 | – |
| Toddler (1 to 2 years) | 45 – 49 | 17.7 – 19.3 | – |
| 2 to 4 years | 47.5 – 51 | 18.7 – 20.1 | – |
| 5 to 8 years | 50.5 – 53 | 19.9 – 20.9 | 6 ⅜ – 6 ⅝ |
| 9 to 12 years | 52 – 55.5 | 20.5 – 21.9 | 6 ½ – 7 |
| Teen | 54 – 58 | 21.3 – 22.8 | 6 ¾ – 7 ¼ |
| Adult woman | 53 – 59.5 | 20.9 – 23.4 | 6 ⅝ – 7 ½ |
| Adult man | 55 – 60.5 | 21.7 – 23.8 | 6 ⅞ – 7 ⅝ |
When to ask a doctor
- A measurement below the 3rd or above the 97th percentile.
- A measurement that crosses two major percentile lines between checkups.
- Fast head growth together with other symptoms, such as vomiting, a bulging soft spot or unusual sleepiness.