1. What is BMI for Children?

BMI (Body Mass Index) for children and teens is calculated the same way as for adults, but the interpretation uses age- and sex-specific percentiles because body composition varies as children grow.

2. How the Calculator Works

The calculator uses the standard BMI formula:

Then compares the result to UK NHS growth charts to determine the percentile category.

3. Understanding BMI Percentiles

Percentile Categories:

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

4. Using the Calculator

Tips: Enter weight in kilograms, height in meters, and exact age (2-18 years). For accurate results, measure height without shoes and weight with minimal clothing.

5. Frequently Asked Questions (FAQ)

Q1: Why use percentiles for children?
A: Children's body composition changes with growth, so percentiles account for normal variations by age and sex.

Q2: Is BMI accurate for all children?
A: BMI is a screening tool but may not reflect body fat in very muscular children or those with certain medical conditions.

Q3: When should I be concerned?
A: Consult a healthcare provider if your child is below 5th percentile or above 85th percentile consistently.

Q4: How often should BMI be checked?
A: NHS recommends annual checks for school-aged children as part of routine health assessments.

Q5: What if my child is above the healthy range?
A: Focus on healthy lifestyle changes - balanced diet, regular physical activity, and adequate sleep - rather than weight loss.