1. What is BMI?

Body Mass Index (BMI) is a measure that uses height and weight to work out if weight is healthy. For children and teens, 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 BMI formula:

Where:

• \( weight \) — Weight in kilograms (kg)
• \( height \) — Height in meters (m)

Note: For children, the BMI number is plotted on growth charts to determine a percentile ranking based on age and gender.

3. Importance of BMI Calculation

Details: BMI is a screening tool to identify potential weight problems in children. It helps assess whether a child is underweight, healthy weight, overweight, or obese.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: What is a healthy BMI for children?
A: Healthy BMI ranges vary by age and gender. Generally between 5th and 85th percentile on growth charts is considered healthy.

Q2: How often should I check my child's BMI?
A: NHS recommends BMI checks as part of routine growth monitoring at key stages (school entry, age 11).

Q3: What if my child's BMI is high?
A: Consult your GP or school nurse. They can assess growth patterns and refer to specialist services if needed.

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

Q5: Where can I get more advice?
A: NHS website provides BMI calculators with percentile charts and advice on healthy lifestyles.