Why the WHO charts
The CDC recommends the WHO Child Growth Standards for children from birth to 2 years in the US, then the CDC growth charts from age 2. The WHO weight-for-age charts are based on breastfed infants, which is why they show slower weight gain after about 3 months than older charts did.
What is "normal"?
The WHO uses cutoffs of 2 standard deviations, which match the 2.3rd and 97.7th percentiles. The charts label them the 2nd and 98th percentiles. A measurement between them falls within the range of the standards. Below the 2nd or above the 98th is a reason for your doctor to look more closely, not a diagnosis.
One measurement is a snapshot
Growth charts are read over time. Your doctor plots each checkup's measurements and looks at the pattern across visits, together with how your baby is feeding and developing. Bring any home measurements to checkups and let your doctor interpret them.
Typical values
| Age | Boys weight (50th) | Girls weight (50th) | Boys length (50th) | Girls length (50th) |
|---|---|---|---|---|
| 0 months | 3.35 kg (7 lb 6 oz) | 3.23 kg (7 lb 2 oz) | 49.88 cm | 49.15 cm |
| 1 months | 4.47 kg (9 lb 14 oz) | 4.19 kg (9 lb 4 oz) | 54.72 cm | 53.69 cm |
| 2 months | 5.57 kg (12 lb 4 oz) | 5.13 kg (11 lb 5 oz) | 58.42 cm | 57.07 cm |
| 3 months | 6.38 kg (14 lb 1 oz) | 5.85 kg (12 lb 14 oz) | 61.43 cm | 59.8 cm |
| 4 months | 7.0 kg (15 lb 7 oz) | 6.42 kg (14 lb 2 oz) | 63.89 cm | 62.09 cm |
| 6 months | 7.93 kg (17 lb 8 oz) | 7.3 kg (16 lb 1 oz) | 67.62 cm | 65.73 cm |
| 9 months | 8.9 kg (19 lb 10 oz) | 8.23 kg (18 lb 2 oz) | 71.97 cm | 70.14 cm |
| 12 months | 9.65 kg (21 lb 4 oz) | 8.95 kg (19 lb 12 oz) | 75.75 cm | 74.02 cm |
| 15 months | 10.31 kg (22 lb 12 oz) | 9.6 kg (21 lb 3 oz) | 79.15 cm | 77.51 cm |
| 18 months | 10.94 kg (24 lb 2 oz) | 10.23 kg (22 lb 9 oz) | 82.26 cm | 80.71 cm |
| 24 months | 12.15 kg (26 lb 13 oz) | 11.48 kg (25 lb 5 oz) | 87.82 cm | 86.42 cm |
Check your own baby with the growth percentile calculator.
Sources: CDC, "Using WHO Growth Standard Charts"; CDC, WHO growth standards data files (birth to 24 months).
