Growth Chart Calculator

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Weight-for-age calculator

Weight-for-age is the simplest growth indicator: it tells you where a child's weight sits relative to other children of the same age and sex. It's most informative under 24 months, when WHO recommends it as a primary measure. After 2 years, pediatricians usually look at BMI-for-age alongside weight-for-age.

This calculator only asks for weight (length/height is hidden). It uses the WHO Child Growth Standards for children under 24 months and the CDC 2000 growth charts for 24 months and older. Switch to a specific reference via the Standard dropdown if your clinician prefers one.

Frequently asked questions

What does 'weight-for-age' mean?

Weight-for-age compares a child's weight to other children of the same age and sex, expressed as a percentile. The 50th percentile is the median — half the reference population weighs more, half weighs less at that age.

Is weight-for-age a good measure of nutrition?

It's a useful screen in the first 2 years but becomes less informative after that because it doesn't account for height. WHO only recommends weight-for-age as a primary indicator through 60 months. After 2 years, BMI-for-age or weight-for-height is preferred.

Why is my baby's percentile different at different visits?

Small fluctuations are normal — percentile is a snapshot. Babies can cross percentile lines in the first 18 months as they settle into their genetic trajectory (canalization). A sustained drop across two or more major bands across several visits is worth discussing with a pediatrician.