Pediatric BMI & Growth
Accurately tracking growth requires comparing a child’s BMI against age-and-gender specific percentiles. Unlike adults, a BMI of 20 can be “obese” for a 6-year-old but “healthy” for a 15-year-old.
This advanced tool uses monthly interpolation of CDC growth charts to determine the BMI Percentile, Z-Score, and the specific Healthy Weight Range for your child’s exact age.
kg
Growth Assessment
CDC INTERPOLATED
—
BMI (kg/m²)
Under
5th
85th
95th
Obese
— Percentile
Weight Status
—
—
Z-Score (SD)
—
Standard deviations from the population mean.
Healthy Weight Range
—
This range maintains a BMI between the 5th and 85th percentile for this specific age.
Clinical Definitions
- Percentile: Compares your child to 100 other children of the same age/gender. e.g., 75th percentile means they have a higher BMI than 75% of their peers.
- Z-Score: A statistical measure of how far a data point is from the mean. A Z-score of 0 is exactly average. +2 or more typically indicates obesity.
- Healthy Range: Defined by the CDC as falling between the 5th and 85th percentiles.
Using the Calculator
1
Input Exact Age
Enter years and months (e.g., 9 years, 6 months). Accuracy here is crucial for the interpolation logic.
2
Measure Height
Measure standing height without shoes. Ensure heels are flat on the floor and head is level.
3
Review Target
Check the “Healthy Weight Range” card. This gives you a tangible goal in kg/lbs rather than just an abstract percentile.
Disclaimer: This tool uses CDC growth chart data (2000). It is a screening tool, not a diagnostic instrument. Body composition (muscle vs fat) is not accounted for. Consult a pediatrician for evaluation.