How to Read Growth Percentiles
Growth percentiles are the primary tool used by pediatricians to assess whether a child is growing adequately. This calculator uses official WHO data for children 0-5 years and CDC references for ages 5-18.
What Percentiles Mean
If your child is at the 50th percentile for weight, it means their weight is exactly average: 50% of peers weigh less and 50% weigh more. A child at the 25th percentile isn't "small" in a negative sense -- they're simply lighter than 75% of peers. WHO considers all values between the 3rd and 97th percentile normal.
WHO Growth Standards
WHO standards were developed in 2006 studying approximately 8,500 children in Brazil, Ghana, India, Norway, Oman, and the USA. They represent optimal growth of breastfed children under favorable conditions, making them a prescriptive standard (how children should grow).
The Importance of Growth Trends
The pediatrician doesn't look at a single point but at the trend across multiple visits. What's concerning is a sudden change, such as dropping from the 50th to the 10th percentile in a few months. A growth slowdown may signal nutritional issues, food intolerances, or other conditions.
When to Consult Your Pediatrician
Consult your pediatrician if:
- Weight or height is below the 3rd percentile or above the 97th
- The child crosses two or more percentile lines up or down
- Growth has stalled for more than 3 months (in the first 2 years)
- There is a large discrepancy between weight and height percentiles