Baby & Child Growth Percentile Calculator

Select your child's sex, enter their birth date and measurement date (or enter age directly), then type in weight, length or height, and optionally head circumference. The results table and percentile charts update instantly — you see every applicable WHO and CDC chart on a single page.

WHO and CDC charts describe different populations. WHO curves model how healthy, primarily breastfed infants grow under optimal conditions. CDC curves describe how American children actually grew across national surveys. A typical 6-to-12-month-old often lands at a different percentile on each because the reference populations differed in feeding methods and demographics.

For US children, the American Academy of Pediatrics recommends WHO growth charts through age 2 and CDC growth charts from age 2 onward. This calculator shows both and highlights the AAP-recommended chart so you can see the clinically preferred reading while still viewing all applicable charts.

Any percentile between the 3rd and 97th is within the normal range. What matters most is that your child tracks consistently along their own growth curve over time. A child steadily at the 15th percentile is growing just as well as one at the 85th — the number itself matters less than the trend across visits.

No. All calculations happen in your browser. If you save a visit, the data is stored in your browser's local storage on your device only. Nothing is sent to any server. You can clear all saved data at any time.

BMI is weight in kilograms divided by height in meters squared (kg/m²). For children and teens aged 2–20, the raw BMI number is then compared against age- and sex-specific CDC reference data to produce a percentile. Unlike adults, where fixed BMI cutoffs apply, children's BMI interpretation depends on age and sex because body composition changes as they grow.