1. What is BMI for Children?

BMI (Body Mass Index) for children and teenagers 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 Does the Calculator Work?

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 child's percentile for their age and gender.

3. Importance of BMI Calculation

Details: BMI percentile is the best indicator of healthy weight for children. It helps identify underweight, healthy weight, overweight, and obesity in children and teens.

4. Using the Calculator

Tips: Enter weight in kg, 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: Why is BMI different for children than adults?
A: Children's body composition changes as they grow, so BMI must be compared to other children of the same age and sex.

Q2: What do the percentile ranges mean?
A: Below 2nd (underweight), 2nd-91st (healthy weight), 91st-98th (overweight), above 98th (obese).

Q3: When should I be concerned about my child's BMI?
A: If your child is below 2nd percentile or above 91st percentile, consult your GP or health visitor.

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: How often should I check my child's BMI?
A: Routine measurements are done at school entry (4-5 years) and in Year 6 (10-11 years), but you can check more often if concerned.