Baby Weight Percentile Calculator
Check your baby's weight against WHO growth standards and find out their percentile and growth status.
50th
Percentile
Normal
Growth Status
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Median for Age (kg)
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Normal Range (kg)
WHO Reference Weights (Boys & Girls)
| Age | Boys Median | Girls Median | Normal Range |
|---|---|---|---|
| Birth | 3.3 kg | 3.2 kg | 2.5–4.4 kg |
| 1 month | 4.5 kg | 4.2 kg | 3.4–5.8 kg |
| 3 months | 6.0 kg | 5.5 kg | 4.6–7.8 kg |
| 6 months | 7.9 kg | 7.3 kg | 6.0–9.8 kg |
| 9 months | 9.2 kg | 8.6 kg | 7.1–11.4 kg |
| 12 months | 10.2 kg | 9.5 kg | 7.8–12.7 kg |
| 18 months | 11.5 kg | 10.9 kg | 8.8–14.6 kg |
| 24 months | 12.7 kg | 12.1 kg | 9.6–16.2 kg |
Frequently Asked Questions
What is a weight percentile for babies?
A weight percentile compares your baby's weight to other babies of the same age and gender. The 50th percentile means your baby weighs more than 50% of babies that age. Any percentile between 5th and 95th is generally considered within the normal range.
My baby is at the 20th percentile — is that worrying?
Not necessarily. What matters more than a single number is consistent growth over time. A baby who stays at the 20th percentile while growing well is healthy. Concern arises when a baby drops significantly across percentile lines (e.g., from 50th to 15th) over multiple visits.
How much should a Nigerian baby weigh at birth?
The average birth weight in Nigeria is approximately 3.1–3.3 kg. Birth weight below 2.5 kg is classified as low birth weight (LBW), which is more common in Nigeria due to factors like malaria, malnutrition, and teenage pregnancy. These babies need extra monitoring.
When should I be concerned about my baby's weight?
Consult your paediatrician if your baby: falls below the 3rd percentile, drops more than 2 major percentile lines, has not regained birth weight by 2 weeks, or shows signs of poor feeding. Regular clinic visits (at 6 weeks, 10 weeks, 14 weeks, 6 months, 9 months, 12 months) are important.
What do I do if my baby is underweight?
See a paediatrician for a full assessment. Common causes include insufficient breast milk, feeding difficulties, infections, or underlying medical conditions. For babies over 6 months, supplementary feeding with nutrient-dense local foods (like akamu fortified with crayfish and groundnut oil) can help.