1. What is BMI?

Body Mass Index (BMI) is a measure that uses height and weight to estimate body fat. For children and teens, BMI is age- and sex-specific and is often referred to as BMI-for-age. It's an important screening tool for weight categories that may lead to health problems.

2. How Does the Calculator Work?

The calculator uses the standard BMI formula adjusted for children:

Where:

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

Note: For children, the BMI number is plotted on growth charts to determine the BMI percentile, which accounts for age and sex differences in body fat.

3. Importance of BMI Calculation for Children

Details: Tracking BMI in children helps identify potential weight problems early. Childhood obesity can lead to health issues like type 2 diabetes, high blood pressure, and high cholesterol.

4. Using the Calculator

Tips: Enter weight in kilograms, height in meters, age in years (2-18), and select gender. For most accurate results, measure height and weight without shoes and heavy clothing.

5. Frequently Asked Questions (FAQ)

Q1: How is children's BMI different from adults?
A: Children's BMI is interpreted relative to other children of the same age and sex, using percentile rankings rather than fixed categories.

Q2: What is a healthy BMI for a child?
A: Generally, BMI between 5th and 85th percentile is considered healthy weight for age and sex.

Q3: When should I be concerned about my child's BMI?
A: Consult a healthcare provider if your child is below 5th percentile (underweight) or above 85th percentile (overweight).

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

Q5: Where can I find NHS BMI growth charts?
A: NHS growth charts are available from your GP or school nurse, and online through official NHS resources.