Enter details
Sex, age in months, and current weight (with an optional height for your records).
Baby Growth Percentile Calculator
Enter your baby's sex, age in months and weight for an approximate weight-for-age percentile based on WHO reference data.
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Approximate weight-for-age percentile
Height is recorded for your own reference only — this tool doesn't calculate a height percentile. Use an official WHO or CDC chart for that.
Rough estimate only, not medical advice. It is not a substitute for official WHO/CDC growth charts or your pediatrician, and shouldn't be used to make care decisions.
How it works
Compare to reference points
The tool interpolates WHO reference weight and spread for that age.
See the estimate
Get an approximate percentile, always paired with a reminder this isn't a diagnosis.
FAQ
How is the percentile calculated?
Weight is compared to interpolated WHO reference median and spread values for the entered age and sex, converted to a percentile using a standard normal distribution approximation.
Is this the same as my pediatrician's chart?
No. This is a simplified approximation using a small set of reference points, not the full official WHO or CDC growth chart curves.
Should I make decisions based on this number?
No. This is a rough estimate only, not medical advice. Always use official WHO/CDC growth charts and talk with your pediatrician about your baby's growth.