1. What is BMI?

Body Mass Index (BMI) is a person's weight in kilograms divided by the square of height in meters. It's a simple screening tool for weight categories that may lead to health problems.

2. How Does the Calculator Work?

The calculator uses the standard BMI formula:

For children and teens (ages 2-20), the calculator also provides weight and BMI percentiles based on CDC growth charts.

3. Importance of BMI and Percentile

Details: BMI is used to screen for weight categories that may lead to health problems. For children, growth charts show how measurements compare with others of the same age and gender.

4. Using the Calculator

Tips: Enter weight in kilograms and height in meters. For percentile calculation, provide age (2-20 years) and gender. All values must be valid (weight > 0, height > 0).

5. Frequently Asked Questions (FAQ)

Q1: What are the BMI categories for adults?
A: Underweight (<18.5), Normal (18.5-24.9), Overweight (25-29.9), Obesity (≥30).

Q2: How are percentiles interpreted for children?
A: Below 5th percentile: underweight; 5th-85th: healthy weight; 85th-95th: overweight; ≥95th: obese.

Q3: Why use different charts for children?
A: Children's body composition varies by age and gender, so their BMI must be compared to peers.

Q4: Are there limitations to BMI?
A: BMI doesn't distinguish between muscle and fat, and may not accurately reflect body fatness in athletes or elderly.

Q5: When should I be concerned about my child's percentile?
A: Consult a healthcare provider if your child is below 5th or above 85th percentile, or if there are sudden changes.