Free Baby Growth Percentile Calculator — WHO Chart
Calculate baby weight, length, and head circumference percentiles using WHO Child Growth Standards. Enter age, sex, and measurements for instant, clear results.
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Results
Weight
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Length
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Head
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Based on the WHO Child Growth Standards (0–24 months) using the LMS method (Lambda / Mu / Sigma) to compute a z-score, converted to percentile via the standard normal distribution. Prototype uses approximate LMS values — verified WHO reference tables will replace these before launch.
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What this percentile means
A percentile compares your baby to other babies of the same age and sex. The 60th percentile for weight means 60% of babies that age and sex weigh less, and 40% weigh more.
There is no "best" percentile. A healthy baby can sit anywhere on the chart. What pediatricians watch for is the trend over time, not a single reading.
If a baby moves sharply across percentile bands between visits, that's worth a conversation with your provider — high or low.
How to use this calculator
- 01Pick your baby's sex and your preferred units.
- 02Enter age in months. Use half-months (e.g. 6.5) for more precision.
- 03Enter at least one measurement — weight, length, or head circumference.
- 04Percentiles update as you type. No button to press.
Common questions
Related calculators
- Children's Height & Weight Percentile Calculator (ages 2–18)
- Percentile Calculator (statistical)
- BMI Calculator — for adults 18+
- Age Calculator
- Premature baby growth adjuster — coming soon
- Infant feeding amount estimator — coming soon