Baby Growth Percentile Calculator
Compare your baby’s weight, height & head circumference to WHO/CDC growth standards
Baby’s Details
Percentile Results
Weight-for-Age
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Height-for-Age
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BMI-for-Age (2–20y)
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Head Circ. (0–5y)
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Percentiles use a smoothed approximation of WHO (0-2y) and CDC (2-20y) growth reference medians/SDs, interpolated between published data points. For precise clinical assessment consult your pediatrician’s official growth chart.
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Frequently Asked Questions
What does percentile mean?
It indicates how your baby compares to other healthy babies of the same age and sex (e.g. the 50th percentile is average).
Is the 50th percentile “average”?
Yes — being at the 50th percentile means the baby sits exactly in the middle of the reference growth chart.
Should I worry if the percentile is low?
Not necessarily. Consistent growth along a curve over time is more important than any single low or high reading.
How is this percentile calculated here?
This tool uses a documented approximation: it interpolates published WHO/CDC median and standard-deviation reference points by age and sex, then converts the resulting z-score to a percentile. It does not use the full official LMS statistical tables, so treat results as indicative, not a diagnostic substitute for your doctor’s chart.