Baby Growth Percentile Calculator
Compare your baby's weight and height to WHO growth chart percentiles (ages 0-24 months).
This tool is for informational and educational purposes only. It is not a substitute for professional financial, medical, legal, or engineering advice. See Terms of Service.
Can't find what you need?
Request a ToolHow to Use the Baby Growth Percentile Calculator
This calculator compares your baby's measurements to WHO growth chart reference data for ages 0-24 months. Here is how to use it:
- Enter your baby's age. Enter the age in months. You can use decimals, for example, 4.5 for 4 months and 2 weeks.
- Select sex. Growth charts differ for boys and girls. Select the appropriate option.
- Enter weight and length. Enter your baby's current weight in kilograms and recumbent length (lying down measurement) in centimeters. These are taken at pediatric checkups.
- Read your results. The calculator shows a percentile for weight and height, along with a category label.
A percentile shows how your baby compares to the reference population. The 50th percentile is the median. Most pediatricians consider any value between the 3rd and 97th percentile to be within the normal range.
About the Baby Growth Percentile Calculator
This calculator uses simplified WHO Multicentre Growth Reference Study data, which represents optimal growth in healthy, breastfed children from diverse populations. The calculator uses an approximation of the LMS (Lambda-Mu-Sigma) method to compute percentiles from median and standard deviation values for key age points.
Percentile is only one data point. A consistent growth trend matters more than any single measurement. A baby who has always been at the 10th percentile for weight is likely healthy. One who drops from the 75th to the 10th percentile over several months may warrant evaluation. Always discuss growth concerns with your pediatrician.
Frequently Asked Questions
What is a normal growth percentile for a baby?
Any percentile between the 3rd and 97th is generally considered within the normal range. There is no single ideal percentile. A baby consistently at the 10th percentile is likely healthy, while a baby who suddenly drops two major percentile lines may need evaluation. Pediatricians look at growth trends over time, not just a single measurement.
What is the difference between weight-for-age and weight-for-length?
Weight-for-age compares your baby's weight to other babies of the same age, giving an overall size comparison. Weight-for-length (or BMI-for-age) compares weight relative to the baby's own length, which is a better indicator of whether a baby is overweight or underweight for their frame. This calculator shows weight-for-age and length-for-age percentiles separately.
My baby is below the 3rd percentile. Should I be worried?
Being below the 3rd percentile does not automatically mean something is wrong. Small parents often have small babies. However, it does warrant a closer look from your pediatrician, who will evaluate feeding, developmental milestones, growth velocity, and family history. If the baby is consistently below the 3rd percentile but growing at a normal rate, that may simply reflect their natural size.
How often should I track my baby's growth?
The American Academy of Pediatrics recommends well-child visits at 1, 2, 4, 6, 9, 12, 15, 18, 24, and 30 months, where growth measurements are taken at every visit. For premature babies, measurements are plotted on adjusted age (corrected for the number of weeks early) until around 2 years of age.