Baby growth chart: weight, length and head size by month

Percentile calculator

Sex

Boy Girl

Date of birth Date measured Weightkglb Length / heightcmin Head circumferencecmin Calculate

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WHO standards by age

Weight-for-age — boys (kg)

Weight-for-age — boys (kg)

Age	−2 SD	−1 SD	Median	+1 SD	+2 SD
Birth	2.5	2.9	3.3 (7.4 lb)	3.9	4.4
1 wk	2.6	3.0	3.5 (7.7 lb)	4.0	4.6
2 wk	2.8	3.2	3.8 (8.3 lb)	4.3	4.9
3 wk	3.1	3.5	4.1 (9.0 lb)	4.7	5.3
4 wk	3.3	3.8	4.4 (9.6 lb)	5.0	5.7
5 wk	3.5	4.1	4.7 (10.3 lb)	5.3	6.0
6 wk	3.8	4.3	4.9 (10.9 lb)	5.6	6.3
7 wk	4.0	4.6	5.2 (11.4 lb)	5.9	6.6
8 wk	4.2	4.8	5.4 (11.9 lb)	6.1	6.9
9 wk	4.4	5.0	5.6 (12.4 lb)	6.4	7.2
10 wk	4.5	5.2	5.8 (12.9 lb)	6.6	7.4
11 wk	4.7	5.3	6.0 (13.3 lb)	6.8	7.6
12 wk	4.9	5.5	6.2 (13.7 lb)	7.0	7.8
3 mo	5.0	5.7	6.4 (14.1 lb)	7.2	8.0
4 mo	5.6	6.2	7.0 (15.4 lb)	7.8	8.7
5 mo	6.0	6.7	7.5 (16.6 lb)	8.4	9.3
6 mo	6.4	7.1	7.9 (17.5 lb)	8.8	9.8
7 mo	6.7	7.4	8.3 (18.3 lb)	9.2	10.3
8 mo	6.9	7.7	8.6 (19.0 lb)	9.6	10.7
9 mo	7.1	8.0	8.9 (19.6 lb)	9.9	11.0
10 mo	7.4	8.2	9.2 (20.2 lb)	10.2	11.4
11 mo	7.6	8.4	9.4 (20.8 lb)	10.5	11.7
12 mo	7.7	8.6	9.6 (21.3 lb)	10.8	12.0
13 mo	7.9	8.8	9.9 (21.8 lb)	11.0	12.3
14 mo	8.1	9.0	10.1 (22.3 lb)	11.3	12.6
15 mo	8.3	9.2	10.3 (22.7 lb)	11.5	12.8
16 mo	8.4	9.4	10.5 (23.2 lb)	11.7	13.1
17 mo	8.6	9.6	10.7 (23.7 lb)	12.0	13.4
18 mo	8.8	9.8	10.9 (24.1 lb)	12.2	13.7
19 mo	8.9	10.0	11.1 (24.6 lb)	12.5	13.9
20 mo	9.1	10.1	11.3 (25.0 lb)	12.7	14.2
21 mo	9.2	10.3	11.5 (25.5 lb)	12.9	14.5
22 mo	9.4	10.5	11.8 (25.9 lb)	13.2	14.7
23 mo	9.5	10.7	12.0 (26.3 lb)	13.4	15.0
24 mo	9.7	10.8	12.2 (26.8 lb)	13.6	15.3

Weight-for-age — girls (kg)

Weight-for-age — girls (kg)

Age	−2 SD	−1 SD	Median	+1 SD	+2 SD
Birth	2.4	2.8	3.2 (7.1 lb)	3.7	4.2
1 wk	2.5	2.9	3.3 (7.4 lb)	3.9	4.4
2 wk	2.7	3.1	3.6 (7.9 lb)	4.1	4.7
3 wk	2.9	3.3	3.8 (8.5 lb)	4.4	5.0
4 wk	3.1	3.6	4.1 (9.0 lb)	4.7	5.4
5 wk	3.3	3.8	4.3 (9.6 lb)	5.0	5.7
6 wk	3.5	4.0	4.6 (10.1 lb)	5.2	6.0
7 wk	3.7	4.2	4.8 (10.6 lb)	5.5	6.2
8 wk	3.8	4.4	5.0 (11.0 lb)	5.7	6.5
9 wk	4.0	4.6	5.2 (11.4 lb)	5.9	6.7
10 wk	4.1	4.7	5.4 (11.8 lb)	6.1	6.9
11 wk	4.3	4.9	5.5 (12.2 lb)	6.3	7.1
12 wk	4.4	5.0	5.7 (12.5 lb)	6.5	7.3
3 mo	4.5	5.2	5.8 (12.9 lb)	6.6	7.5
4 mo	5.0	5.7	6.4 (14.2 lb)	7.3	8.2
5 mo	5.4	6.1	6.9 (15.2 lb)	7.8	8.8
6 mo	5.7	6.5	7.3 (16.1 lb)	8.2	9.3
7 mo	6.0	6.8	7.6 (16.8 lb)	8.6	9.8
8 mo	6.3	7.0	7.9 (17.5 lb)	9.0	10.2
9 mo	6.5	7.3	8.2 (18.1 lb)	9.3	10.5
10 mo	6.7	7.5	8.5 (18.7 lb)	9.6	10.9
11 mo	6.9	7.7	8.7 (19.2 lb)	9.9	11.2
12 mo	7.0	7.9	8.9 (19.7 lb)	10.1	11.5
13 mo	7.2	8.1	9.2 (20.2 lb)	10.4	11.8
14 mo	7.4	8.3	9.4 (20.7 lb)	10.6	12.1
15 mo	7.6	8.5	9.6 (21.2 lb)	10.9	12.4
16 mo	7.7	8.7	9.8 (21.6 lb)	11.1	12.6
17 mo	7.9	8.9	10.0 (22.1 lb)	11.4	12.9
18 mo	8.1	9.1	10.2 (22.6 lb)	11.6	13.2
19 mo	8.2	9.2	10.4 (23.0 lb)	11.8	13.5
20 mo	8.4	9.4	10.6 (23.5 lb)	12.1	13.7
21 mo	8.6	9.6	10.9 (23.9 lb)	12.3	14.0
22 mo	8.7	9.8	11.1 (24.4 lb)	12.5	14.3
23 mo	8.9	10.0	11.3 (24.8 lb)	12.8	14.6
24 mo	9.0	10.2	11.5 (25.3 lb)	13.0	14.8

Length-for-age — boys (cm)

Length-for-age — boys (cm)

Age	−2 SD	−1 SD	Median	+1 SD	+2 SD
Birth	46.1	48.0	49.9	51.8	53.7
1 wk	47.3	49.2	51.1	53.0	54.9
2 wk	48.5	50.4	52.3	54.3	56.2
3 wk	49.5	51.5	53.4	55.3	57.2
4 wk	50.5	52.4	54.4	56.3	58.3
5 wk	51.4	53.4	55.3	57.3	59.2
6 wk	52.3	54.3	56.2	58.2	60.2
7 wk	53.1	55.1	57.1	59.1	61.0
8 wk	53.9	55.9	57.9	59.9	61.9
9 wk	54.6	56.6	58.7	60.7	62.7
10 wk	55.4	57.4	59.4	61.4	63.4
11 wk	56.0	58.1	60.1	62.1	64.1
12 wk	56.7	58.7	60.8	62.8	64.8
3 mo	57.3	59.4	61.4	63.5	65.5
4 mo	59.7	61.8	63.9	66.0	68.0
5 mo	61.7	63.8	65.9	68.0	70.1
6 mo	63.3	65.5	67.6	69.8	71.9
7 mo	64.8	67.0	69.2	71.3	73.5
8 mo	66.2	68.4	70.6	72.8	75.0
9 mo	67.5	69.7	72.0	74.2	76.5
10 mo	68.7	71.0	73.3	75.6	77.9
11 mo	69.9	72.2	74.5	76.9	79.2
12 mo	71.0	73.4	75.7	78.1	80.5
13 mo	72.1	74.5	76.9	79.3	81.8
14 mo	73.1	75.6	78.0	80.5	83.0
15 mo	74.1	76.6	79.1	81.7	84.2
16 mo	75.0	77.6	80.2	82.8	85.4
17 mo	76.0	78.6	81.2	83.9	86.5
18 mo	76.9	79.6	82.3	85.0	87.7
19 mo	77.7	80.5	83.2	86.0	88.8
20 mo	78.6	81.4	84.2	87.0	89.8
21 mo	79.4	82.3	85.1	88.0	90.9
22 mo	80.2	83.1	86.0	89.0	91.9
23 mo	81.0	83.9	86.9	89.9	92.9
24 mo	81.0	84.1	87.1	90.2	93.2

Length-for-age — girls (cm)

Length-for-age — girls (cm)

Age	−2 SD	−1 SD	Median	+1 SD	+2 SD
Birth	45.4	47.3	49.1	51.0	52.9
1 wk	46.6	48.4	50.3	52.2	54.1
2 wk	47.7	49.6	51.5	53.4	55.3
3 wk	48.6	50.5	52.5	54.4	56.3
4 wk	49.5	51.4	53.4	55.3	57.3
5 wk	50.3	52.3	54.2	56.2	58.2
6 wk	51.1	53.1	55.1	57.1	59.0
7 wk	51.8	53.8	55.8	57.8	59.9
8 wk	52.5	54.6	56.6	58.6	60.6
9 wk	53.2	55.2	57.3	59.3	61.4
10 wk	53.8	55.9	57.9	60.0	62.1
11 wk	54.4	56.5	58.6	60.7	62.7
12 wk	55.0	57.1	59.2	61.3	63.4
3 mo	55.6	57.7	59.8	61.9	64.0
4 mo	57.8	59.9	62.1	64.3	66.4
5 mo	59.6	61.8	64.0	66.2	68.5
6 mo	61.2	63.5	65.7	68.0	70.3
7 mo	62.7	65.0	67.3	69.6	71.9
8 mo	64.0	66.4	68.7	71.1	73.5
9 mo	65.3	67.7	70.1	72.6	75.0
10 mo	66.5	69.0	71.5	73.9	76.4
11 mo	67.7	70.3	72.8	75.3	77.8
12 mo	68.9	71.4	74.0	76.6	79.2
13 mo	70.0	72.6	75.2	77.8	80.5
14 mo	71.0	73.7	76.4	79.1	81.7
15 mo	72.0	74.8	77.5	80.2	83.0
16 mo	73.0	75.8	78.6	81.4	84.2
17 mo	74.0	76.8	79.7	82.5	85.4
18 mo	74.9	77.8	80.7	83.6	86.5
19 mo	75.8	78.8	81.7	84.7	87.6
20 mo	76.7	79.7	82.7	85.7	88.7
21 mo	77.5	80.6	83.7	86.7	89.8
22 mo	78.4	81.5	84.6	87.7	90.8
23 mo	79.2	82.3	85.5	88.7	91.9
24 mo	79.3	82.5	85.7	88.9	92.2

Head circumference-for-age — boys (cm)

Head circumference-for-age — boys (cm)

Age	−2 SD	−1 SD	Median	+1 SD	+2 SD
Birth	31.9	33.2	34.5	35.7	37.0
1 wk	32.7	33.9	35.2	36.4	37.6
2 wk	33.5	34.7	35.9	37.0	38.2
3 wk	34.2	35.4	36.5	37.7	38.9
4 wk	34.8	35.9	37.1	38.3	39.4
5 wk	35.3	36.4	37.6	38.8	39.9
6 wk	35.7	36.9	38.1	39.2	40.4
7 wk	36.1	37.3	38.5	39.7	40.8
8 wk	36.5	37.7	38.9	40.0	41.2
9 wk	36.9	38.1	39.2	40.4	41.6
10 wk	37.2	38.4	39.6	40.8	41.9
11 wk	37.5	38.7	39.9	41.1	42.3
12 wk	37.9	39.0	40.2	41.4	42.6
3 mo	38.1	39.3	40.5	41.7	42.9
4 mo	39.2	40.4	41.6	42.8	44.0
5 mo	40.1	41.4	42.6	43.8	45.0
6 mo	40.9	42.1	43.3	44.6	45.8
7 mo	41.5	42.7	44.0	45.2	46.4
8 mo	42.0	43.3	44.5	45.8	47.0
9 mo	42.5	43.7	45.0	46.3	47.5
10 mo	42.9	44.1	45.4	46.7	47.9
11 mo	43.2	44.5	45.8	47.0	48.3
12 mo	43.5	44.8	46.1	47.4	48.6
13 mo	43.8	45.0	46.3	47.6	48.9
14 mo	44.0	45.3	46.6	47.9	49.2
15 mo	44.2	45.5	46.8	48.1	49.4
16 mo	44.4	45.7	47.0	48.3	49.6
17 mo	44.6	45.9	47.2	48.5	49.8
18 mo	44.7	46.0	47.4	48.7	50.0
19 mo	44.9	46.2	47.5	48.9	50.2
20 mo	45.0	46.4	47.7	49.0	50.4
21 mo	45.2	46.5	47.8	49.2	50.5
22 mo	45.3	46.6	48.0	49.3	50.7
23 mo	45.4	46.8	48.1	49.5	50.8
24 mo	45.5	46.9	48.3	49.6	51.0

Head circumference-for-age — girls (cm)

Head circumference-for-age — girls (cm)

Age	−2 SD	−1 SD	Median	+1 SD	+2 SD
Birth	31.5	32.7	33.9	35.1	36.2
1 wk	32.2	33.4	34.6	35.7	36.9
2 wk	32.9	34.1	35.2	36.4	37.5
3 wk	33.5	34.7	35.8	37.0	38.2
4 wk	34.0	35.2	36.4	37.5	38.7
5 wk	34.5	35.7	36.8	38.0	39.2
6 wk	34.9	36.1	37.3	38.5	39.6
7 wk	35.3	36.5	37.7	38.9	40.1
8 wk	35.6	36.8	38.0	39.2	40.4
9 wk	35.9	37.1	38.4	39.6	40.8
10 wk	36.2	37.4	38.7	39.9	41.1
11 wk	36.5	37.7	39.0	40.2	41.4
12 wk	36.8	38.0	39.3	40.5	41.7
3 mo	37.1	38.3	39.5	40.8	42.0
4 mo	38.1	39.3	40.6	41.8	43.1
5 mo	38.9	40.2	41.5	42.7	44.0
6 mo	39.6	40.9	42.2	43.5	44.8
7 mo	40.2	41.5	42.8	44.1	45.5
8 mo	40.7	42.0	43.4	44.7	46.0
9 mo	41.2	42.5	43.8	45.2	46.5
10 mo	41.5	42.9	44.2	45.6	46.9
11 mo	41.9	43.2	44.6	45.9	47.3
12 mo	42.2	43.5	44.9	46.3	47.6
13 mo	42.4	43.8	45.2	46.5	47.9
14 mo	42.7	44.1	45.4	46.8	48.2
15 mo	42.9	44.3	45.7	47.0	48.4
16 mo	43.1	44.5	45.9	47.2	48.6
17 mo	43.3	44.7	46.1	47.4	48.8
18 mo	43.5	44.9	46.2	47.6	49.0
19 mo	43.6	45.0	46.4	47.8	49.2
20 mo	43.8	45.2	46.6	48.0	49.4
21 mo	44.0	45.3	46.7	48.1	49.5
22 mo	44.1	45.5	46.9	48.3	49.7
23 mo	44.3	45.6	47.0	48.4	49.8
24 mo	44.4	45.8	47.2	48.6	50.0

How to read it

WHO built these standards from healthy children in six countries, raised in conditions that favour healthy growth, including breastfeeding. The median is the middle: half of babies are above it and half below. About 68% of babies fall between −1 SD and +1 SD, and about 95% between −2 SD and +2 SD.

Doctors look at the trend across several measurements more than at any single number. Length is measured lying down up to 2 years; the calculator switches to standing height after that, as WHO does.

These are reference values, not a diagnosis. If a measurement worries you, or sits below −2 SD or above +2 SD, ask your paediatrician.

Source: World Health Organization — WHO Child Growth Standards (2006)

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