Child BMI Calculator (2–20)
Child BMI Calculator (2–20)
Calculate child BMI with age- and sex-specific percentiles.
What is BMI?
Body Mass Index (BMI) relates weight and height to quickly estimate nutritional status. It’s useful for screening, but it’s **not a diagnosis**: body composition, age, sex, ethnicity and specific conditions (e.g., athletes, pregnancy, older adults) can change interpretation.
Formula
The formula is BMI = weight (kg) / height (m)². If you enter pounds and feet/inches, the calculator converts to metric before applying the formula.
Variables
- Weight (
W) — kg, lb · 1 lb = 0.45359237 kg - Height (
H) — m, cm, ft/in · 1 in = 2.54 cm · 1 ft = 30.48 cm
Examples
- 1. 70 kg and 175 cm → BMI ≈ 22.9 (normal).
Child & Teen Reference Ranges
For children and teens (≈ 2–20 years), BMI is interpreted using age
| BMI | Category |
|---|---|
| < 5th percentile | Underweight |
| 5th to < 85th percentile | Healthy |
| 85th to < 95th percentile | Overweight |
| ≥ 95th percentile | Obesity |
Child & Teen Mode (≈ 2–20 years)
For **children and teens (≈ 2–20 years)**, interpretation uses **BMI-for-age percentiles** by sex. Categories follow percentile thresholds (e.g., < p5 underweight; p5–p85 healthy; p85–p95 overweight; ≥ p95 obesity). The reference (WHO or CDC) can vary by country and is defined in the country override.
Limitations
While BMI is a useful screening tool, it has limitations. Consider these points:
- BMI is a screening tool and does not directly measure body fat.
- It may misclassify muscular individuals as overweight or obese.
- Does not account for fat distribution, which affects health risk.
- Not suitable for all populations (e.g., athletes, pregnant )
Important Notes
- This tool is informational and not a medical diagnosis.
- For specific medical conditions, consult a healthcare professional.