1. What is BMI?

BMI (Body Mass Index) is a measure that uses height and weight to estimate body fat. 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

Note: For UK children, this value should be compared to age and sex-specific percentiles.

3. Importance of BMI Calculation for Kids

Details: BMI-for-age is the recommended measure for screening overweight and obesity in children aged 2-18 years. It helps identify potential weight problems that may lead to health issues.

4. Using the Calculator

Tips: Enter weight in kilograms and height in meters. For accurate results, measurements should be taken with minimal clothing and no shoes.

5. Frequently Asked Questions (FAQ)

Q1: How is child BMI different from adult BMI?
A: Children's BMI is compared to growth charts for their age and sex, as body composition changes with growth and development.

Q2: What are the percentile categories for UK children?
A: Typically: Underweight (<2nd), Healthy weight (2nd-90th), Overweight (91st-97th), Obese (≥98th).

Q3: When should I be concerned about my child's BMI?
A: If your child's BMI is below the 2nd percentile or above the 91st percentile, consult a healthcare professional.

Q4: Are there limitations to BMI for children?
A: BMI doesn't distinguish between fat and muscle mass. Athletic children may have high BMI without excess fat.

Q5: Where can I find UK growth charts?
A: UK-WHO growth charts are available from the Royal College of Paediatrics and Child Health website.