Head circumference chart for boys
The median and outer lines at each age. Open a row for the full percentile table, a chart and a CSV.
WHO 2006 · CDC 2000 · retrieved 2026-10-05Same chart for girls
| Age | Standard | Lower line | Median | Upper line | Median (imperial) |
|---|---|---|---|---|---|
| Birth | WHO | 31.9 cm (2nd) | 34.5 cm | 37.0 cm (98th) | 13.6 in |
| 1 month | WHO | 34.9 cm (2nd) | 37.3 cm | 39.6 cm (98th) | 14.7 in |
| 2 months | WHO | 36.8 cm (2nd) | 39.1 cm | 41.5 cm (98th) | 15.4 in |
| 3 months | WHO | 38.1 cm (2nd) | 40.5 cm | 42.9 cm (98th) | 16.0 in |
| 4 months | WHO | 39.2 cm (2nd) | 41.6 cm | 44.0 cm (98th) | 16.4 in |
| 5 months | WHO | 40.1 cm (2nd) | 42.6 cm | 45.0 cm (98th) | 16.8 in |
| 6 months | WHO | 40.9 cm (2nd) | 43.3 cm | 45.8 cm (98th) | 17.1 in |
| 7 months | WHO | 41.5 cm (2nd) | 44.0 cm | 46.4 cm (98th) | 17.3 in |
| 8 months | WHO | 42.0 cm (2nd) | 44.5 cm | 47.0 cm (98th) | 17.5 in |
| 9 months | WHO | 42.5 cm (2nd) | 45.0 cm | 47.5 cm (98th) | 17.7 in |
| 10 months | WHO | 42.9 cm (2nd) | 45.4 cm | 47.9 cm (98th) | 17.9 in |
| 11 months | WHO | 43.2 cm (2nd) | 45.8 cm | 48.3 cm (98th) | 18.0 in |
| 12 months | WHO | 43.5 cm (2nd) | 46.1 cm | 48.6 cm (98th) | 18.1 in |
| 13 months | WHO | 43.8 cm (2nd) | 46.3 cm | 48.9 cm (98th) | 18.2 in |
| 14 months | WHO | 44.0 cm (2nd) | 46.6 cm | 49.2 cm (98th) | 18.3 in |
| 15 months | WHO | 44.2 cm (2nd) | 46.8 cm | 49.4 cm (98th) | 18.4 in |
| 16 months | WHO | 44.4 cm (2nd) | 47.0 cm | 49.6 cm (98th) | 18.5 in |
| 17 months | WHO | 44.6 cm (2nd) | 47.2 cm | 49.8 cm (98th) | 18.6 in |
| 18 months | WHO | 44.7 cm (2nd) | 47.4 cm | 50.0 cm (98th) | 18.7 in |
| 19 months | WHO | 44.9 cm (2nd) | 47.5 cm | 50.2 cm (98th) | 18.7 in |
| 20 months | WHO | 45.0 cm (2nd) | 47.7 cm | 50.4 cm (98th) | 18.8 in |
| 21 months | WHO | 45.2 cm (2nd) | 47.8 cm | 50.5 cm (98th) | 18.8 in |
| 22 months | WHO | 45.3 cm (2nd) | 48.0 cm | 50.7 cm (98th) | 18.9 in |
| 23 months | WHO | 45.4 cm (2nd) | 48.1 cm | 50.8 cm (98th) | 18.9 in |
| 2 years | CDC 2000 | 46.0 cm (3rd) | 48.7 cm | 51.3 cm (97th) | 19.2 in |
| 3 years | CDC 2000 | 46.4 cm (3rd) | 49.7 cm | 52.6 cm (97th) | 19.6 in |