Online Tool Store
Baby Growth Percentile Lookup
Estimate a baby's weight-for-age percentile using WHO growth standard reference values, for ages 0-24 months. Runs entirely in your browser.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Estimated percentile
Median weight for this age
How the growth percentile lookup works
- Select your baby's sex and enter their age in months (0-24) and current weight in kilograms.
- The tool interpolates WHO weight-for-age reference values for that exact age.
- See the estimated percentile and the median weight for babies of that age and sex.
FAQ
How is the percentile calculated?
Using the LMS method with WHO weight-for-age growth standard data - the same statistical approach pediatric growth charts are built on, converting a weight into a z-score and then a percentile.
What does a percentile mean?
A 60th percentile means the baby weighs more than roughly 60% of babies of the same age and sex in the reference population. It's a comparison point, not a judgment of health.
Is a low or high percentile a cause for concern?
Not on its own - what matters most to pediatricians is a consistent growth trend over time, not a single percentile reading. Sudden jumps or drops are more meaningful than the percentile itself.
How accurate is this compared to an official growth chart?
It uses interpolated reference values and is meant for general guidance - always use your pediatrician's official growth chart and assessment for medical decisions.
How we compare
| Feature | Online Tool Store | Reading a printed chart | Pediatric growth tracking app |
|---|---|---|---|
| Exact percentile for any age | ✓ | ✗ | ✓ |
| Instant, no account needed | ✓ | ✓ | ✗ |
| Free | ✓ | ✓ | ✗ |
A quick reference between pediatrician visits - always confirm with your doctor's official growth chart.