Baby boy weight chart by month
WHO weight-for-age percentiles for baby boys at every month from birth to 24 months, in kg and in pounds (lbs). Use the calculator to find your son’s weight percentile for their exact age. For girls, see the baby girl weight chart by month.
Enter a date of birth and at least one measurement to see the percentile.
Key numbers
- The WHO median birth weight for boys is 3.3 kg (7.4 lb); the 3rd to 97th percentile at birth runs from 2.5 kg (5.5 lb) to 4.3 kg (9.6 lb).
- The median is 6.4 kg (14.1 lb) at 3 months, 7.9 kg (17.5 lb) at 6 months, 8.9 kg (19.6 lb) at 9 months and 9.6 kg (21.3 lb) at 12 months.
- Median weight doubles birth weight at about 4 months and is about 2.9 times birth weight at 1 year.
- At 2 years the median is 12.2 kg (26.8 lb).
Baby boy weight by month in kg (WHO)
Weight in kg at each percentile. The median (50th) is the average weight for that age.
| Age | 3th | 15th | Median | 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 | 10.5 |
| 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 |
| 24 months | 9.8 | 10.8 | 12.2 | 13.7 | 15.1 |
Baby boy weight by month in pounds (lbs) (WHO)
Weight in lb at each percentile. The median (50th) is the average weight for that age.
| Age | 3th | 15th | Median | 85th | 97th |
|---|---|---|---|---|---|
| Birth | 5.5 | 6.3 | 7.4 | 8.5 | 9.6 |
| 1 month | 7.6 | 8.6 | 9.9 | 11.3 | 12.6 |
| 2 months | 9.7 | 10.8 | 12.3 | 13.9 | 15.4 |
| 3 months | 11.2 | 12.4 | 14.1 | 15.9 | 17.5 |
| 4 months | 12.4 | 13.7 | 15.4 | 17.3 | 19.0 |
| 5 months | 13.4 | 14.7 | 16.6 | 18.6 | 20.3 |
| 6 months | 14.2 | 15.6 | 17.5 | 19.6 | 21.4 |
| 7 months | 14.9 | 16.3 | 18.3 | 20.5 | 22.4 |
| 8 months | 15.4 | 17.0 | 19.0 | 21.2 | 23.3 |
| 9 months | 16.0 | 17.5 | 19.6 | 22.0 | 24.0 |
| 10 months | 16.4 | 18.0 | 20.2 | 22.6 | 24.8 |
| 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 |
| 24 months | 21.6 | 23.8 | 26.8 | 30.2 | 33.2 |
How to read this chart
A percentile compares your baby’s weight with other boys of the same age. At the 50th percentile, half of healthy boys measure more and half measure less. Anything between the 3rd and the 97th percentile is within the usual range on the WHO chart.
The trend matters more than one number. A baby who stays near the same percentile line from visit to visit is growing steadily, whether that line is the 15th or the 85th. More in What percentile should my baby be?and How much weight should a baby gain per week?
Common questions
What is a normal birth weight for a baby boy?
On the WHO standard, the 3rd to 97th percentile at birth for boys runs from 2.5 kg (5.5 lb) to 4.3 kg (9.6 lb), with a median of 3.3 kg (7.4 lb). Most newborns lose some weight in the first days and are back to birth weight by 10 to 14 days.
What is the average weight of a baby boy by month?
The WHO median, the usual "average", is 4.5 kg (9.9 lb) at 1 month, 5.6 kg (12.3 lb) at 2 months, 6.4 kg (14.1 lb) at 3 months, 7.0 kg (15.4 lb) at 4 months, 7.9 kg (17.5 lb) at 6 months, 8.6 kg (19.0 lb) at 8 months, 8.9 kg (19.6 lb) at 9 months, 9.6 kg (21.3 lb) at 12 months, 10.9 kg (24.1 lb) at 18 months. The table on this page lists every month to 24 months.
What is a normal weight for a 9-month-old boy?
On the WHO standard, the 3rd to 97th percentile at 9 months runs from 7.2 kg (16.0 lb) to 10.9 kg (24.0 lb), with a median of 8.9 kg (19.6 lb).
What is a normal weight for a 1-year-old boy?
On the WHO standard, the 3rd to 97th percentile at 12 months runs from 7.8 kg (17.3 lb) to 11.8 kg (26.1 lb), with a median of 9.6 kg (21.3 lb).
Should I use the WHO or the CDC chart?
The CDC recommends the WHO growth charts for children under 2 years in the United States, and the CDC charts from age 2. Values on this page are from the WHO Child Growth Standards.
Follow your baby’s curve over time
Growthling plots every checkup on the WHO or CDC chart and shows the percentile for each one. Free to sign up.
Start tracking freeAlso: baby weight chart for girls and boys · baby boy length chart · growth chart calculator for boys
Source: WHO Child Growth Standards, weight-for-age, percentiles computed from the WHO LMS tables at each whole month. For information only; not medical advice.