How is the growth percentile calculated?

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Accepted Answer

This site uses LMS tables from the WHO 2006 Child Growth Standards. For each sex and age in days, an L, M, S triple gives Z = ((X/M)^L − 1) / (L·S) when L ≠ 0, then the normal CDF maps Z to a percentile from 0 to 100. The WHO standards are designed to be ethnicity-neutral for ages 0–60 months (0–1856 days). Percentiles describe population distribution, not individual health: below 3 or above 97 can still be normal, and a child's own trend over time matters more than a single measurement. For clinical assessment, see a pediatrician.