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 standard BMI formula:

Where:

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

Note: For children, the BMI number is plotted on the UK NHS growth charts to determine the weight status percentile.

3. Importance of BMI Calculation for Children

Details: BMI is an important screening tool to identify potential weight problems in children. It helps healthcare professionals assess whether a child is underweight, healthy weight, overweight, or obese for their age and height.

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 without shoes and weight with minimal clothing.

5. Frequently Asked Questions (FAQ)

Q1: What is a healthy BMI for children?
A: Healthy BMI ranges vary by age and sex. The NHS uses growth charts to determine if a child's BMI is in a healthy range for their age and gender.

Q2: How often should my child's BMI be checked?
A: The NHS recommends BMI checks as part of routine health assessments, typically during school entry (age 4-5) and in year 6 (age 10-11).

Q3: What if my child's BMI is high?
A: A high BMI may indicate overweight or obesity. Consult your GP or health visitor for advice on healthy lifestyle changes.

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

Q5: Where can I find NHS BMI percentile charts?
A: NHS BMI percentile charts are available on the NHS website or from your GP surgery.