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Baby Growth Percentile Calculator
Track your baby's growth against WHO standards. Enter weight, length, or head circumference to see percentile rankings and z-scores from birth to 24 months.
Sex
Units
months
lbs
in
in
Quick Facts
Average birth weight7.5 lbs (3.4 kg)
Doubles birth weight by~4-5 months
Triples birth weight by~12 months
WHO standard rangeBirth to 24 months
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How to Use This Calculator
- Select your baby's sex (boy or girl).
- Choose the measurement type: Weight-for-Age, Length-for-Age, or Head Circumference.
- Enter your baby's age in months (0-24).
- Enter the measurement value in your preferred units.
- Click Calculate to see the percentile ranking, z-score, and growth status.
The Formula
Percentile is calculated using the WHO LMS method: Z = ((Value/M)^L - 1) / (L × S), where L, M, S are age- and sex-specific parameters from WHO growth standards.Frequently Asked Questions
A percentile shows how your baby compares to others of the same age and sex. The 50th percentile is average. The 25th percentile means 25% of babies weigh less. Healthy babies can be anywhere from the 5th to 95th percentile.