What Is the WHO Weight-for-Age Chart?
The WHO weight-for-age chart shows how your child's weight compares to healthy children of the same age and sex worldwide. The WHO standards were developed using data from optimally-fed, healthy children in 6 countries, representing the gold standard for how children should grow.
Key insight: A single measurement shows where your child is today. Tracking multiple measurements over time reveals their growth trajectory — which is much more meaningful.
How to Read the Chart
The chart displays weight on the vertical axis and age on the horizontal axis, with curved lines representing different percentiles (3rd, 15th, 50th, 85th, 97th). Your child's measurement is plotted relative to these curves.
The 50th percentile (median) is the middle line — half of healthy children weigh more, half weigh less. The normal range spans the 3rd to 97th percentiles (z-score −2 to +2).
When to Use This Calculator
- Routine monitoring: Track weight at each pediatric visit
- Concern about weight: Assess if your child is underweight or overweight
- Preterm follow-up: Use corrected age until age 2
- Feeding assessment: Evaluate growth response to feeding interventions
Track weight over time with full charts
GrowChart plots your child's growth trajectory on WHO percentile curves automatically.