1. What is BMI for Children?

BMI (Body Mass Index) for children is calculated the same way as for adults, but the interpretation is different. For children, BMI is age and gender-specific and is referred to as "BMI-for-age."

2. How BMI is Calculated for Kids

The calculator uses the standard BMI formula:

Where:

• \( weight \) — Child's weight in kilograms
• \( height \) — Child's height in meters

Note: The result is then compared to growth charts for children of the same age and gender.

3. Understanding BMI Percentiles

Percentile Ranges:

• Underweight: Less than 2nd percentile
• Healthy weight: 2nd to 90th percentile
• Overweight: 91st to 97th percentile
• Obese: 98th percentile or above

4. Using the Calculator

Tips: Measure height without shoes and weight with minimal clothing. For most accurate results, use measurements taken by a healthcare professional.

5. Frequently Asked Questions (FAQ)

Q1: Why is BMI different for children than adults?
A: Children's body composition changes as they grow, so their BMI must be compared to other children of the same age and gender.

Q2: What if my child is above the 91st percentile?
A: Consult your GP or health visitor for advice. They may recommend lifestyle changes or further assessments.

Q3: Is BMI accurate for very athletic children?
A: BMI doesn't distinguish between muscle and fat, so athletic children may have a high BMI without excess fat.

Q4: How often should I check my child's BMI?
A: Routine measurements are typically done at school entry (age 4-5) and in year 6 (age 10-11) in the UK.

Q5: Where can I find official NHS growth charts?
A: NHS growth charts are available at RCPCH website.