Baby Weight Percentile Calculator

A weight percentile shows how your baby's weight compares to other babies of the same age and sex. For example, if your baby is in the 75th percentile, they weigh more than 75% of babies their age and less than 25%. Percentiles between the 5th and 95th are generally considered within the normal range.

The World Health Organization (WHO) Child Growth Standards describe normal child growth from birth to 5 years under optimal environmental conditions. They are based on a study of approximately 8,500 children from diverse ethnic backgrounds and cultural settings (Brazil, Ghana, India, Norway, Oman and the USA). These standards are the international benchmark used by pediatricians worldwide.

The LMS method is a statistical technique used to create smooth percentile curves. L represents skewness, M is the median, and S is the coefficient of variation. Together, these parameters allow precise calculation of any percentile for any age, accounting for the fact that weight distributions are not perfectly symmetrical.

Not necessarily! Healthy babies come in all sizes. What matters most is that your baby follows their own growth curve consistently over time. A baby who consistently tracks at the 25th percentile is typically just as healthy as one at the 75th. Sudden changes in percentile—either up or down—are what pediatricians watch for. Always discuss concerns with your healthcare provider.

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