Monitoring a child’s growth is vital for assessing their health and development. The WHO Growth Chart Calculator is an online tool designed to help parents, pediatricians, and caregivers determine how a child’s measurements—such as weight, height, BMI, and head circumference—compare to World Health Organization (WHO) growth standards. This powerful resource provides percentile rankings based on age and gender, helping to identify potential growth concerns early.
WHO Growth Chart Calculator
What Is the WHO Growth Chart?
The World Health Organization developed growth standards based on data from healthy children living in optimal environments across six countries. These standards serve as a global benchmark for healthy child development and provide percentile curves for:
- Weight-for-age
- Height-for-age
- BMI-for-age
- Head circumference-for-age (infants)
The percentile indicates the relative position of the child’s measurement among children of the same age and gender. For example, a child in the 70th percentile for weight weighs more than 70% of peers.
How to Use the WHO Growth Chart Calculator
Using the WHO Growth Chart Calculator is quick and easy. Here’s a step-by-step guide:
Step 1: Input Child’s Details
- Age (in months or years)
- Gender (male/female)
- Weight (kg or lbs)
- Height/Length (cm or inches)
- Head Circumference (for children under 3 years)
Step 2: Select Measurement Type
Choose one or more of the following:
- Weight-for-age
- Height-for-age
- BMI-for-age
- Head circumference-for-age
Step 3: View Results
Click the “Calculate” button. The tool will return:
- Percentile score (e.g., 45th percentile)
- Z-score (standard deviation from the mean)
- Growth status (e.g., normal, underweight, overweight, stunted)
WHO Growth Chart Percentile Categories
Percentiles are interpreted as follows:
| Percentile | Interpretation |
|---|---|
| < 3rd | Severely under or stunted |
| 3rd–15th | Underweight or short stature |
| 15th–85th | Normal growth |
| 85th–97th | Overweight or tall |
| > 97th | Obese or very tall |
These interpretations depend on the type of measurement used.
Z-Score Formula (Simplified)
The Z-score indicates how far a child’s measurement is from the mean of the reference population:
Z = (Observed Value – Median) / Standard Deviation
The WHO database provides median and standard deviation values for each age/gender group to plug into the formula.
Example Calculation
Child Details:
- Age: 24 months
- Gender: Female
- Weight: 12.5 kg
- Height: 84 cm
Using the WHO database for a 2-year-old girl:
- Median weight: 12.2 kg
- SD: 1.1 kg
Z = (12.5 – 12.2) / 1.1 = 0.27
A Z-score of 0.27 corresponds to approximately the 61st percentile — within the normal growth range.
Why Use the WHO Growth Chart Calculator?
- ✅ Clinically Approved Standards: Based on WHO data, the most trusted in the world.
- ✅ Instant Results: Calculate percentiles within seconds.
- ✅ Visual Tracking: Helps identify stunting, undernutrition, or obesity.
- ✅ Growth Monitoring: Regular use supports early intervention.
- ✅ Multiple Metrics: Track weight, height, BMI, and head circumference.
When to Use This Calculator
- During routine pediatric visits
- Before vaccinations
- Monitoring at-risk children (premature, low birth weight)
- Comparing growth between siblings
- Creating growth reports for school or medical evaluations
Additional Tips for Parents
- Always measure height and weight under similar conditions (e.g., no shoes).
- For infants, measure recumbent length instead of standing height.
- If unsure about percentiles or Z-scores, consult a pediatrician.
Limitations
- The tool is based on WHO standards, not regional/national norms.
- It does not diagnose medical conditions—it highlights potential areas of concern.
- Measurements should be taken correctly for accurate results.
20 Frequently Asked Questions (FAQs)
1. What is the WHO Growth Chart Calculator?
It’s a tool that compares a child’s height, weight, and head circumference to WHO growth standards.
2. Who can use this calculator?
Parents, doctors, nurses, nutritionists, and childcare professionals.
3. What is a percentile in growth measurement?
It shows how a child’s measurement compares to peers of the same age and sex.
4. What is a Z-score?
A standardized value showing how far a child’s measurement is from the population mean.
5. Is this tool accurate for premature babies?
Yes, but corrected age (based on due date) should be used up to 2 years of age.
6. How often should I use it?
Every few months during the first two years, and every 6–12 months afterward.
7. Does it support metric and imperial units?
Yes, most tools accept both (kg/lbs, cm/inches).
8. What if my child is under the 3rd percentile?
It may indicate undernutrition or growth delay; consult a pediatrician.
9. What if my child is over the 97th percentile?
This could point to obesity or advanced growth; again, consult a pediatrician.
10. Can I use it for children over 5 years?
Yes, WHO charts are valid up to 5 years; for older kids, use CDC or country-specific references.
11. What does “BMI-for-age” mean?
It assesses whether a child’s weight is appropriate for their height and age.
12. Is head circumference important?
Yes, especially for infants—it reflects brain growth and skull development.
13. Do growth charts differ by gender?
Yes, boys and girls grow at slightly different rates.
14. Can I print the results?
Yes, most calculators offer downloadable or printable reports.
15. What if my child jumps percentiles?
Small fluctuations are normal, but large shifts warrant medical attention.
16. Does this calculator work for twins?
Yes, but twins may naturally grow a bit slower than singletons.
17. How is this different from CDC growth charts?
WHO charts reflect ideal growth from breastfed children worldwide; CDC charts are based on U.S. population data.
18. Can poor diet affect percentile rankings?
Yes, inadequate nutrition is a major factor in poor growth trends.
19. How do I measure my child accurately?
Use a baby scale for infants, and a stadiometer for height. Always measure under the same conditions.
20. Is this tool free to use?
Yes, it is completely free and available online.
Final Thoughts
The WHO Growth Chart Calculator is a trusted and essential tool for understanding your child’s growth in a global context. Whether you’re a concerned parent or a healthcare professional, tracking weight, height, BMI, and head circumference using WHO standards gives insight into the child’s health and nutrition. Early detection of growth abnormalities can lead to better outcomes through timely intervention.