Pediatric BMI Percentile Calculator Formula
Understand the math behind the pediatric bmi percentile calculator. Each variable explained with a worked example.
Formulas Used
BMI
bmi = (weight_lbs * 703) / (height_inches * height_inches)BMI Prime (vs 85th percentile)
bmi_prime = (weight_lbs * 703) / (height_inches * height_inches) / (14 + age * 0.5)Variables
| Variable | Description | Default |
|---|---|---|
weight_lbs | Weight(lbs) | 70 |
height_inches | Height(inches) | 54 |
age | Age(years) | 10 |
How It Works
Pediatric BMI
For children aged 2-19, BMI is calculated the same as adults but interpreted differently using age- and sex-specific percentile charts.
BMI = (Weight in lbs x 703) / (Height in inches)^2
Weight Status Categories
| Percentile | Category | |---|---| | <5th | Underweight | | 5th-84th | Healthy weight | | 85th-94th | Overweight | | 95th+ | Obese |
Note: This calculator computes BMI. For exact percentile, use CDC growth charts with the child's age and sex.
Worked Example
A 10-year-old weighing 70 lbs, 54 inches tall.
weight_lbs = 70height_inches = 54age = 10
- 01BMI = (70 x 703) / (54 x 54)
- 02= 49,210 / 2,916
- 03= 16.9
Ready to run the numbers?
Open Pediatric BMI Percentile Calculator