head circumference percentiles P3–P97, Hong Kong SAR

Hong Kong SAR’s published head circumference figures, P3 to P97 month by month, up to 18 years. Boys and girls separately.

boy

Age in years runs along the bottom and head circumference（cm） up the side. The five lines are, from the bottom, the 3rd, 15th, 50th, 85th and 97th percentiles, ranging from 32.4 to 58.9. The full figures are in the table above.

Hong Kong SAR percentile curves for head circumference, boy.

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yearsmonths

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Hong Kong SAR · head circumference, boy（cm）
Age	P3	P15	P50	P85	P97
0 months	32.4	33.2	34.2	35.3	36.1
1 months	34.9	35.8	36.9	38.0	38.9
2 months	36.8	37.7	38.9	40.1	41.1
3 months	38.2	39.2	40.4	41.6	42.6
4 months	39.3	40.3	41.6	42.8	43.9
5 months	40.3	41.3	42.6	43.9	44.9
6 months	41.1	42.1	43.4	44.7	45.8
7 months	41.8	42.8	44.1	45.4	46.5
8 months	42.3	43.3	44.7	46.0	47.1
9 months	42.8	43.8	45.1	46.5	47.6
10 months	43.2	44.2	45.6	46.9	48.1
11 months	43.5	44.6	45.9	47.3	48.4
12 months	43.8	44.9	46.3	47.6	48.8
13 months	44.1	45.2	46.5	47.9	49.1
14 months	44.3	45.4	46.8	48.2	49.3
15 months	44.6	45.6	47.0	48.4	49.6
16 months	44.7	45.8	47.2	48.6	49.8
17 months	44.9	46.0	47.4	48.8	49.9
18 months	45.1	46.1	47.5	48.9	50.1
19 months	45.2	46.3	47.7	49.1	50.2
20 months	45.3	46.4	47.8	49.2	50.4
21 months	45.4	46.5	47.9	49.3	50.5
22 months	45.6	46.6	48.0	49.4	50.6
23 months	45.7	46.8	48.1	49.5	50.7
2 years	45.8	46.9	48.2	49.7	50.8
2y 3m	46.1	47.1	48.5	49.9	51.1
2y 6m	46.3	47.4	48.8	50.2	51.4
2y 9m	46.6	47.6	49.0	50.5	51.6
3 years	46.8	47.9	49.3	50.7	51.9
3y 3m	47.0	48.1	49.5	50.9	52.1
3y 6m	47.2	48.3	49.6	51.1	52.2
3y 9m	47.3	48.4	49.8	51.2	52.4
4 years	47.5	48.6	49.9	51.4	52.6
4y 3m	47.6	48.7	50.1	51.5	52.7
4y 6m	47.7	48.8	50.2	51.6	52.8
4y 9m	47.9	49.0	50.3	51.8	52.9
5 years	48.0	49.1	50.4	51.9	53.1
5y 6m	48.2	49.3	50.7	52.1	53.3
6 years	48.5	49.6	50.9	52.4	53.6
6y 6m	48.7	49.8	51.2	52.6	53.8
7 years	48.9	50.0	51.4	52.9	54.1
7y 6m	49.1	50.2	51.6	53.1	54.3
8 years	49.3	50.5	51.9	53.3	54.6
8y 6m	49.5	50.7	52.1	53.6	54.8
9 years	49.7	50.9	52.3	53.8	55.1
9y 6m	49.9	51.1	52.5	54.1	55.4
10 years	50.1	51.3	52.8	54.3	55.6
10y 6m	50.3	51.5	53.0	54.6	55.9
11 years	50.5	51.7	53.2	54.8	56.2
11y 6m	50.7	51.9	53.5	55.1	56.5
12 years	51.0	52.2	53.7	55.4	56.8
12y 6m	51.2	52.4	54.0	55.7	57.1
13 years	51.4	52.6	54.2	55.9	57.4
13y 6m	51.6	52.9	54.5	56.2	57.6
14 years	51.9	53.1	54.7	56.4	57.9
14y 6m	52.1	53.3	54.9	56.7	58.1
15 years	52.3	53.5	55.1	56.9	58.3
15y 6m	52.5	53.7	55.3	57.0	58.5
16 years	52.6	53.9	55.5	57.2	58.6
16y 6m	52.8	54.0	55.6	57.3	58.8
17 years	52.9	54.1	55.7	57.4	58.8
17y 6m	53.0	54.2	55.8	57.4	58.9
18 years	53.1	54.3	55.8	57.5	58.9

girl

Age in years runs along the bottom and head circumference（cm） up the side. The five lines are, from the bottom, the 3rd, 15th, 50th, 85th and 97th percentiles, ranging from 32 to 56.5. The full figures are in the table above.

Hong Kong SAR percentile curves for head circumference, girl.

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yearsmonths

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Hong Kong SAR · head circumference, girl（cm）
Age	P3	P15	P50	P85	P97
0 months	32.0	32.8	33.8	34.8	35.6
1 months	34.3	35.1	36.1	37.2	38.1
2 months	36.0	36.9	38.0	39.1	40.0
3 months	37.4	38.2	39.4	40.5	41.5
4 months	38.4	39.4	40.5	41.7	42.7
5 months	39.3	40.3	41.4	42.6	43.6
6 months	40.1	41.1	42.2	43.5	44.5
7 months	40.8	41.7	43.0	44.2	45.2
8 months	41.4	42.3	43.6	44.8	45.8
9 months	41.9	42.9	44.1	45.4	46.4
10 months	42.3	43.3	44.5	45.8	46.9
11 months	42.7	43.7	44.9	46.2	47.2
12 months	43.0	44.0	45.2	46.5	47.6
13 months	43.2	44.2	45.5	46.8	47.8
14 months	43.5	44.5	45.7	47.0	48.1
15 months	43.7	44.7	45.9	47.2	48.3
16 months	43.8	44.8	46.1	47.4	48.5
17 months	44.0	45.0	46.3	47.6	48.6
18 months	44.2	45.2	46.4	47.7	48.8
19 months	44.3	45.3	46.6	47.9	48.9
20 months	44.4	45.5	46.7	48.0	49.1
21 months	44.6	45.6	46.9	48.2	49.2
22 months	44.7	45.7	47.0	48.3	49.3
23 months	44.8	45.8	47.1	48.4	49.5
2 years	44.9	46.0	47.2	48.5	49.6
2y 3m	45.2	46.3	47.6	48.9	49.9
2y 6m	45.5	46.6	47.9	49.2	50.2
2y 9m	45.7	46.8	48.1	49.4	50.5
3 years	45.9	47.0	48.3	49.6	50.7
3y 3m	46.1	47.2	48.5	49.8	50.8
3y 6m	46.3	47.3	48.6	50.0	51.0
3y 9m	46.4	47.5	48.8	50.1	51.2
4 years	46.6	47.6	49.0	50.3	51.4
4y 3m	46.7	47.8	49.1	50.4	51.5
4y 6m	46.8	47.9	49.3	50.6	51.7
4y 9m	47.0	48.0	49.4	50.7	51.8
5 years	47.1	48.2	49.5	50.9	52.0
5y 6m	47.3	48.4	49.7	51.1	52.2
6 years	47.5	48.6	50.0	51.4	52.5
6y 6m	47.7	48.8	50.2	51.6	52.8
7 years	47.8	49.0	50.4	51.8	53.0
7y 6m	48.1	49.2	50.6	52.1	53.3
8 years	48.3	49.4	50.9	52.4	53.6
8y 6m	48.5	49.7	51.1	52.7	54.0
9 years	48.8	49.9	51.4	53.0	54.3
9y 6m	49.1	50.2	51.7	53.3	54.7
10 years	49.4	50.5	52.0	53.6	55.0
10y 6m	49.7	50.8	52.3	53.9	55.3
11 years	50.0	51.1	52.6	54.2	55.6
11y 6m	50.2	51.3	52.8	54.4	55.8
12 years	50.4	51.6	53.0	54.6	56.0
12y 6m	50.6	51.8	53.2	54.8	56.1
13 years	50.8	51.9	53.4	54.9	56.2
13y 6m	50.9	52.1	53.5	55.0	56.3
14 years	51.0	52.2	53.6	55.1	56.4
14y 6m	51.1	52.2	53.7	55.2	56.4
15 years	51.1	52.3	53.7	55.2	56.5
15y 6m	51.1	52.3	53.7	55.2	56.5
16 years	51.1	52.3	53.7	55.2	56.5
16y 6m	51.1	52.3	53.8	55.2	56.4
17 years	51.1	52.3	53.8	55.2	56.4
17y 6m	51.1	52.3	53.8	55.2	56.4
18 years	51.1	52.3	53.8	55.2	56.4

About this table

These figures were read off the published charts rather than from an official table of numbers. For clinical use, the Department of Health’s own charts are the reference.