What is a growth percentile?

A percentile shows how your baby compares to other babies of the same age and sex. For example, a weight at the 60th percentile means your baby weighs more than 60% of babies the same age and sex in the WHO reference population.

Which standard does this calculator use?

This tool uses the WHO Child Growth Standards (2006), the global reference used by pediatricians worldwide for children aged 0–24 months. The data is based on children raised under optimal conditions in Brazil, Ghana, India, Norway, Oman, and the United States.

What percentile range is considered normal?

Any value between the 3rd and 97th percentile is generally considered within the normal range. However, a single measurement means less than a growth trend over time — a baby consistently at the 10th percentile may be perfectly healthy. Always consult your pediatrician.

Should I worry if my baby is below the 5th percentile?

Not necessarily. Low percentiles may reflect normal variation, genetic factors, or temporary feeding changes. What matters most is a consistent growth curve. Talk to your pediatrician if your baby crosses two major percentile lines downward over several measurements.

How accurate are the results?

Results are based on tabulated LMS parameters from WHO growth standards. The calculator uses the LMS (Lambda-Mu-Sigma) method to convert measurements to z-scores and then to percentiles, matching the precision of clinical WHO charts.

What is the LMS method?

The LMS method accounts for the skewness of growth distributions. L (Box-Cox power), M (median), and S (coefficient of variation) are tabulated for each age. A z-score is computed from these values, then converted to a percentile using the standard normal distribution.

Baby Growth Percentile

Name: Baby Growth Percentile
Availability: InStock
Author: Nham Vu

Enter your baby's age, sex, weight, length, and head circumference to instantly see growth percentiles based on WHO reference data.

Baby Details

Sex

Age (months)

Units

Weight (kg)

Length / Height (cm)

Head Circumference (cm, optional)

Fill in the details on the left and click Calculate Percentiles.

Summary

Enter your baby's age, sex, weight, length, and head circumference to instantly see growth percentiles based on WHO reference data.

How it works

Select your baby's sex (boy or girl).
Enter the baby's age in whole months (0–24).
Enter the baby's weight in kilograms or pounds.
Enter the baby's length in centimeters or inches.
Optionally enter head circumference to get that percentile too.
Click "Calculate" to see all percentiles on the WHO growth chart.

Use cases

Track your infant's growth between pediatric check-ups.
Understand whether your baby's weight is on track for their age and sex.
Monitor head circumference development in the first two years.
Compare growth measurements against WHO international standards.
Prepare questions for your pediatrician with accurate percentile data.
Spot potential growth concerns early by tracking trends over time.

Frequently Asked Questions

Last updated: 2026-06-20 · Reviewed by Nham Vu