1. What is BMI?

Body Mass Index (BMI) is a simple calculation using a person's height and weight. The formula is BMI = kg/m² where kg is a person's weight in kilograms and m² is their height in meters squared. For children, BMI is age- and sex-specific and is often referred to as BMI-for-age.

2. How Does the Calculator Work?

The calculator uses the standard BMI formula:

Where:

• \( weight \) — Body weight in kilograms
• \( height \) — Height in meters

Explanation: The formula calculates body mass per unit of height squared to estimate body fatness.

3. Importance of BMI Calculation

Details: BMI is a screening tool to identify possible weight problems in children. For children, BMI is plotted on growth charts to determine percentile ranking compared to peers of the same age and sex.

4. Using the Calculator

Tips: Enter weight in kilograms and height in meters. All values must be valid (weight > 0, height > 0). For children, the calculated BMI should be compared to CDC growth charts.

5. Frequently Asked Questions (FAQ)

Q1: How is BMI different for children?
A: For children, BMI is age- and sex-specific and is interpreted relative to growth charts rather than fixed categories used for adults.

Q2: What are the BMI categories for children?
A: CDC defines child BMI categories as: Underweight (<5th percentile), Healthy weight (5th-85th), Overweight (85th-95th), Obese (≥95th).

Q3: Can this calculator be used during pregnancy?
A: Standard BMI calculations are not recommended during pregnancy as weight gain patterns differ significantly.

Q4: What are limitations of BMI?
A: BMI doesn't directly measure body fat and can be misleading for muscular individuals or those with different body compositions.

Q5: Where can I find CDC growth charts?
A: CDC growth charts are available at https://www.cdc.gov/growthcharts/clinical_charts.htm