1. What is BMI for Children?

BMI (Body Mass Index) for children and adolescents is calculated the same way as for adults, but the results are interpreted differently. For children, BMI is age and sex-specific and is compared to growth charts to determine a percentile ranking.

2. How the Calculator Works

The calculator uses the standard BMI formula:

Where:

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

Explanation: The result is then compared to UK growth charts to determine the percentile for the child's age and gender.

3. Understanding Percentiles

Details: Percentiles show how a child's BMI compares to others of the same age and gender. The NHS categories are:

• Below 5th percentile: Underweight
• 5th to 85th percentile: Healthy weight
• 85th to 95th percentile: Overweight
• Above 95th percentile: Obese

4. Using the Calculator

Tips: Enter weight in kg, height in meters, and exact age (2-18 years). For accurate results, measurements should be taken with minimal clothing and no shoes.

5. Frequently Asked Questions (FAQ)

Q1: Why use BMI for children instead of adults?
A: Children's body composition changes as they grow, so their BMI must be compared to others of the same age and sex.

Q2: How often should my child's BMI be checked?
A: The NHS recommends annual checks as part of routine health assessments.

Q3: What if my child is very muscular?
A: BMI may overestimate body fat in muscular children. Additional assessments may be needed.

Q4: Where can I find official NHS growth charts?
A: NHS growth charts are available at RCPCH website.

Q5: What should I do if my child is in an unhealthy range?
A: Consult your GP or a pediatric dietitian for personalized advice and support.