1. What is BMI?

Body Mass Index (BMI) is a measure that uses height and weight to assess whether a person is a healthy weight. For children, BMI is age and gender-specific and shown as a percentile. For adults, BMI categories are fixed ranges.

2. How Does the Calculator Work?

The calculator uses the standard BMI formula:

For children, the result is compared to growth charts to determine the percentile. For adults, fixed categories are used:

• Underweight: BMI less than 18.5
• Healthy weight: BMI 18.5 to 24.9
• Overweight: BMI 25 to 29.9
• Obese: BMI 30 or higher

3. Importance of BMI Calculation

Details: BMI is a simple screening tool to identify potential weight problems. For children, tracking BMI over time shows growth patterns. For adults, BMI categories correlate with health risks.

4. Using the Calculator

Tips:

• For children: Enter exact age and gender for accurate percentile calculation
• Measure height without shoes
• Weigh in light clothing
• Use metric units (kg and meters)

5. Frequently Asked Questions (FAQ)

Q1: Is BMI accurate for athletes?
A: BMI may overestimate body fat in muscular individuals as it doesn't distinguish between muscle and fat.

Q2: How often should children's BMI be checked?
A: NHS recommends annual BMI checks for children as part of growth monitoring.

Q3: What if my child is below the 5th percentile?
A: Consult your GP as this may indicate undernutrition or other health issues.

Q4: Are there different charts for different ethnicities?
A: The NHS uses the same charts for all ethnicities, though some groups may have different health risks at the same BMI.

Q5: Where can I get more detailed growth charts?
A: The NHS Growth Charts are available from the Royal College of Paediatrics and Child Health website.