Baby Boy Weight Chart (WHO, 0 to 5 Years)

Weight chart for boys by month

Values at the 3rd, 15th, 50th (median), 85th and 97th percentiles, calculated from the WHO LMS tables. Switch between kg and lb.

Weight in kg by age, WHO percentiles for boys
Age	3rd	15th	50th	85th	97th
Birth	2.5	2.9	3.3	3.9	4.3
1 month	3.4	3.9	4.5	5.1	5.7
2 months	4.4	4.9	5.6	6.3	7.0
3 months	5.1	5.6	6.4	7.2	7.9
4 months	5.6	6.2	7.0	7.9	8.6
5 months	6.1	6.7	7.5	8.4	9.2
6 months	6.4	7.1	7.9	8.9	9.7
7 months	6.7	7.4	8.3	9.3	10.2
8 months	7.0	7.7	8.6	9.6	10.6
9 months	7.2	7.9	8.9	10.0	10.9
10 months	7.5	8.2	9.2	10.3	11.2
11 months	7.7	8.4	9.4	10.5	11.5
12 months	7.8	8.6	9.6	10.8	11.8
13 months	8.0	8.8	9.9	11.1	12.1
14 months	8.2	9.0	10.1	11.3	12.4
15 months	8.4	9.2	10.3	11.6	12.7
16 months	8.5	9.4	10.5	11.8	12.9
17 months	8.7	9.6	10.7	12.0	13.2
18 months	8.9	9.7	10.9	12.3	13.5
19 months	9.0	9.9	11.1	12.5	13.7
20 months	9.2	10.1	11.3	12.7	14.0
21 months	9.3	10.3	11.5	13.0	14.3
22 months	9.5	10.5	11.8	13.2	14.5
23 months	9.7	10.6	12.0	13.4	14.8
2 years	9.8	10.8	12.1	13.7	15.1
2 years 3 months	10.3	11.3	12.7	14.4	15.9
2 years 6 months	10.7	11.8	13.3	15.0	16.6
2 years 9 months	11.1	12.2	13.8	15.7	17.3
3 years	11.4	12.7	14.3	16.3	18.0
3 years 3 months	11.8	13.1	14.8	16.9	18.7
3 years 6 months	12.2	13.5	15.3	17.5	19.4
3 years 9 months	12.5	13.9	15.9	18.1	20.1
4 years	12.9	14.3	16.3	18.7	20.9
4 years 3 months	13.3	14.7	16.8	19.3	21.6
4 years 6 months	13.6	15.2	17.3	19.9	22.3
4 years 9 months	13.9	15.6	17.8	20.5	23.0
5 years	14.3	16.0	18.3	21.1	23.8

Weight in lb by age, WHO percentiles for boys
Age	3rd	15th	50th	85th	97th
Birth	5.5	6.3	7.4	8.5	9.6
1 month	7.6	8.5	9.8	11.3	12.5
2 months	9.7	10.8	12.3	13.9	15.4
3 months	11.2	12.4	14.0	15.8	17.4
4 months	12.4	13.7	15.4	17.3	19.0
5 months	13.4	14.7	16.6	18.5	20.3
6 months	14.2	15.6	17.5	19.6	21.5
7 months	14.9	16.3	18.3	20.5	22.4
8 months	15.5	17.0	19.0	21.3	23.3
9 months	16.0	17.5	19.6	22.0	24.0
10 months	16.4	18.0	20.2	22.6	24.7
11 months	16.9	18.5	20.8	23.2	25.4
12 months	17.3	19.0	21.3	23.8	26.1
13 months	17.7	19.4	21.8	24.4	26.7
14 months	18.1	19.9	22.3	24.9	27.3
15 months	18.5	20.3	22.7	25.5	27.9
16 months	18.8	20.7	23.2	26.0	28.5
17 months	19.2	21.1	23.7	26.5	29.1
18 months	19.6	21.5	24.1	27.1	29.7
19 months	19.9	21.9	24.6	27.6	30.3
20 months	20.3	22.3	25.0	28.1	30.9
21 months	20.6	22.7	25.5	28.6	31.5
22 months	20.9	23.0	25.9	29.1	32.1
23 months	21.3	23.4	26.3	29.6	32.6
2 years	21.6	23.8	26.8	30.2	33.2
2 years 3 months	22.6	24.9	28.1	31.7	35.0
2 years 6 months	23.5	26.0	29.3	33.1	36.6
2 years 9 months	24.4	26.9	30.5	34.5	38.2
3 years	25.2	27.9	31.6	35.9	39.8
3 years 3 months	26.0	28.8	32.7	37.2	41.3
3 years 6 months	26.8	29.8	33.8	38.5	42.8
3 years 9 months	27.7	30.7	34.9	39.9	44.4
4 years	28.4	31.6	36.0	41.2	46.0
4 years 3 months	29.2	32.5	37.1	42.5	47.5
4 years 6 months	30.0	33.4	38.2	43.9	49.2
4 years 9 months	30.7	34.3	39.3	45.2	50.8
5 years	31.5	35.2	40.4	46.6	52.4

How to read this chart

Find your boy's age on the bottom, then the measurement on the side. Where the two meet tells you his percentile. On the 25th percentile, 25 out of 100 healthy boys the same age measure less and 75 measure more. That is completely normal.

Follow the curve. A boy who keeps to roughly the same line from visit to visit is usually growing well, whatever the line.
Watch for big jumps. Crossing two or more major percentile lines up or down is worth a chat with your doctor.
Look at the whole picture. Weight, length and head size are read together, alongside how he is feeding, sleeping and developing.

How to measure at home

Weigh your baby naked or in a dry nappy, on the same scale each time. Home scales are less precise than clinic scales. Read our full guide on how to measure your baby at home.

Other WHO growth charts

Frequently asked questions

What is a normal weight for a baby boy?

Anything between the 3rd and 97th percentile on the WHO chart is within the normal range. What matters most is that his measurements follow a similar curve over time.

Is the 50th percentile the goal?

No. The 50th percentile is the middle, not a target. A boy on the 10th or the 90th percentile who stays on that curve is usually growing well.

Which chart should I use for my baby boy?

Most countries use the WHO Child Growth Standards for children from birth to 5 years, including the UK and the US CDC for children under 2. This chart uses those WHO tables.

When should I talk to a doctor about my boy's weight?

Talk to your doctor or health visitor if a measurement falls below the 3rd or above the 97th percentile, if it crosses two or more major percentile lines, or any time you are worried.