Boys Head Circumference-for-Age Chart

The full percentile table and chart (0-24 months, WHO), P3 through P97, for boys.

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Age	Source	P3	P10	P25	P50	P75	P90	P97
0 mo	WHO	32.1 cm	32.8 cm	33.6 cm	34.5 cm	35.3 cm	36.1 cm	36.9 cm
1 mo	WHO	35.1 cm	35.8 cm	36.5 cm	37.3 cm	38.1 cm	38.8 cm	39.5 cm
2 mo	WHO	36.9 cm	37.6 cm	38.3 cm	39.1 cm	39.9 cm	40.6 cm	41.3 cm
3 mo	WHO	38.3 cm	39.0 cm	39.7 cm	40.5 cm	41.3 cm	42.0 cm	42.7 cm
4 mo	WHO	39.4 cm	40.1 cm	40.8 cm	41.6 cm	42.4 cm	43.2 cm	43.9 cm
5 mo	WHO	40.3 cm	41.0 cm	41.7 cm	42.6 cm	43.4 cm	44.1 cm	44.8 cm
6 mo	WHO	41.0 cm	41.8 cm	42.5 cm	43.3 cm	44.2 cm	44.9 cm	45.6 cm
7 mo	WHO	41.7 cm	42.4 cm	43.1 cm	44.0 cm	44.8 cm	45.6 cm	46.3 cm
8 mo	WHO	42.2 cm	42.9 cm	43.7 cm	44.5 cm	45.4 cm	46.1 cm	46.9 cm
9 mo	WHO	42.6 cm	43.4 cm	44.2 cm	45.0 cm	45.8 cm	46.6 cm	47.4 cm
10 mo	WHO	43.0 cm	43.8 cm	44.6 cm	45.4 cm	46.3 cm	47.0 cm	47.8 cm
11 mo	WHO	43.4 cm	44.1 cm	44.9 cm	45.8 cm	46.6 cm	47.4 cm	48.2 cm
12 mo	WHO	43.6 cm	44.4 cm	45.2 cm	46.1 cm	46.9 cm	47.7 cm	48.5 cm
13 mo	WHO	43.9 cm	44.7 cm	45.5 cm	46.3 cm	47.2 cm	48.0 cm	48.8 cm
14 mo	WHO	44.1 cm	44.9 cm	45.7 cm	46.6 cm	47.5 cm	48.3 cm	49.0 cm
15 mo	WHO	44.3 cm	45.1 cm	45.9 cm	46.8 cm	47.7 cm	48.5 cm	49.3 cm
16 mo	WHO	44.5 cm	45.3 cm	46.1 cm	47.0 cm	47.9 cm	48.7 cm	49.5 cm
17 mo	WHO	44.7 cm	45.5 cm	46.3 cm	47.2 cm	48.1 cm	48.9 cm	49.7 cm
18 mo	WHO	44.9 cm	45.7 cm	46.5 cm	47.4 cm	48.3 cm	49.1 cm	49.9 cm
19 mo	WHO	45.0 cm	45.8 cm	46.6 cm	47.5 cm	48.4 cm	49.2 cm	50.0 cm
20 mo	WHO	45.2 cm	46.0 cm	46.8 cm	47.7 cm	48.6 cm	49.4 cm	50.2 cm
21 mo	WHO	45.3 cm	46.1 cm	46.9 cm	47.8 cm	48.7 cm	49.6 cm	50.4 cm
22 mo	WHO	45.4 cm	46.3 cm	47.1 cm	48.0 cm	48.9 cm	49.7 cm	50.5 cm
23 mo	WHO	45.6 cm	46.4 cm	47.2 cm	48.1 cm	49.0 cm	49.9 cm	50.7 cm
2y	WHO	45.7 cm	46.5 cm	47.3 cm	48.3 cm	49.2 cm	50.0 cm	50.8 cm

Sources

WHO Child Growth Standards (2006) — who.int (retrieved 2026-09-15)

These are population reference tables, not a diagnosis. For a single percentile computed for your own child, use the head circumference percentile calculator (who) instead of reading it off this table by eye.