What are the WHO Growth Curves?
The World Health Organization (WHO) growth curves are international standards published in 2006, based on a study of healthy children from 6 different countries. They are the most widely used reference worldwide for assessing child growth.
What Does This Calculator Measure?
- Weight for age: compares the child's weight with the WHO reference
- Height for age: compares the child's height with the reference
- BMI for age: assesses the weight/height ratio by age
How to Interpret Percentiles
| Percentile | Interpretation |
|---|---|
| Below 3 | Low weight or height - see a pediatrician |
| 3 to 15 | Low normal range |
| 15 to 85 | Normal range |
| 85 to 97 | High normal range |
| Above 97 | Possible overweight or tall stature |
This calculator is a reference tool. It does not replace professional medical evaluation. Always consult your pediatrician for a complete interpretation of your child's growth.
What is the Z-Score?
The Z-score indicates how many standard deviations a value is from the median. A Z of 0 is exactly the median (50th percentile). A Z between −2 and +2 is considered normal.
How to read the result
A single percentile value matters less than the trend: a child who consistently tracks the 15th percentile with steady growth is normal, while a sudden drop across percentiles (for example, from 50 to 10) deserves medical review. Percentiles compare your child with the reference population of healthy children, so "50th percentile" means half of the reference children weigh less.
Measure at the same time of day, without shoes, and use the same equipment. For infants, weight is most reliable in the first year; length measurements are harder to take accurately at home.
Frequently asked questions
Pediatric check-ups are usually monthly in the first year, quarterly in the second year, and semiannual afterwards. Your pediatrician will tell you the ideal frequency.
Not necessarily. What matters is the growth trend. A child who is always at the 15th percentile but grows steadily is normal. Sudden changes are more concerning.
Yes, WHO curves are considered a universal standard for children aged 0 to 5, regardless of ethnic origin, since they were based on children from diverse countries.
Standard WHO curves cover 0 to 5 years. For older children (5-19 years), WHO has different reference curves.
Yes, tall parents tend to have children at higher percentiles and vice versa. The pediatrician considers these factors in the evaluation.
Related calculators
- BMI: assess weight relative to height
- Ideal weight: healthy weight ranges
- Pregnancy weight gain: healthy growth from the start