1. What is BMI for Children?

BMI (Body Mass Index) is a measure that uses height and weight to estimate body fat. For children, BMI is age- and sex-specific and is referred to as BMI-for-age. It's compared against UK growth charts to determine percentile.

2. How Does the Calculator Work?

The calculator uses the standard BMI formula adapted for pounds and inches:

Where:

• \( weight \) — Child's weight in pounds (lbs)
• \( height \) — Child's height in inches
• 703 — Conversion factor for imperial units

Note: This result should be plotted on UK-specific BMI-for-age growth charts to determine the percentile.

3. Importance of BMI Calculation

Details: BMI-for-age is the most common screening tool for weight status in children. It helps identify potential weight problems that might lead to health issues.

4. Using the Calculator

Tips: Measure weight to the nearest 0.1 pound and height to the nearest 0.1 inch. For most accurate results, measure in the morning before eating.

5. Frequently Asked Questions (FAQ)

Q1: What do BMI percentiles mean?
A: Underweight (<5th percentile), Healthy weight (5th-85th), Overweight (85th-95th), Obese (≥95th percentile).

Q2: How often should my child's BMI be checked?
A: Typically at annual check-ups, or more frequently if weight concerns exist.

Q3: Are there limitations to BMI for children?
A: BMI doesn't distinguish between fat and muscle, so athletic children may show higher BMI without excess fat.

Q4: What's different about UK BMI charts?
A: UK charts are based on British growth patterns and may differ slightly from US or WHO charts.

Q5: When should I be concerned about my child's BMI?
A: Consult your GP if your child is below 5th or above 85th percentile, or if there are rapid changes.