Baby Weight Calculator
Instantly check your baby’s weight percentile based on WHO growth standards. Free, accurate tracking tool for parents and caregivers.
Check Your Baby’s Weight Percentile
Enter your baby’s age, gender, and current weight below to get an instant estimation of their growth percentile based on World Health Organization (WHO) standards.
Baby Details
Enter your baby’s information to see the growth breakdown
Growth Breakdown
Estimated WHO percentile equivalents
WHO Weight Milestones
Typical weight milestones (50th percentile / median) for infants during their first two years of life.
| Age | Boys (Median kg) | Girls (Median kg) | Typical Milestone |
|---|---|---|---|
| Birth (0 mo) | 3.3 kg | 3.2 kg | Baseline |
| 3 Months | 6.4 kg | 5.8 kg | Rapid Growth |
| 6 Months | 7.9 kg | 7.3 kg | Doubles Birth Weight |
| 9 Months | 8.9 kg | 8.2 kg | Crawling Stage |
| 12 Months | 9.6 kg | 8.9 kg | Triples Birth Weight |
| 18 Months | 10.9 kg | 10.2 kg | Toddler Transition |
| 24 Months | 12.2 kg | 11.5 kg | Steady Growth |
Baby Growth FAQ
Everything you need to know about understanding infant growth charts and weight percentiles.
A healthy baby weight can fall anywhere between the 5th and 95th percentiles on the WHO growth charts. The 50th percentile represents the median or average weight. Consistent growth along a baby’s own curve is more important than the specific percentile number.
Baby weight percentiles are calculated by comparing your baby’s weight to a large reference population of babies of the same age and sex. For example, if a baby is in the 70th percentile, it means they weigh more than 70% of babies of the same age and sex, and less than 30%.
Most full-term babies double their birth weight by around 4 to 6 months of age, and triple it by their first birthday. Premature babies may follow a different timeline and are often tracked using adjusted age.
Not necessarily. Babies come in all shapes and sizes, and genetics play a significant role. However, if your baby’s weight drops significantly across percentile lines (e.g., from the 50th to the 15th), or if they are below the 5th percentile, it is best to consult your pediatrician or health visitor.