1. What is BMI Percentile By Age?

BMI (Body Mass Index) percentile by age is a measure used to assess whether a child's weight is appropriate for their height, age, and sex. 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 BMI formula:

Where:

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

Explanation: The BMI value is then plotted on CDC growth charts to determine the percentile ranking compared to children of the same age and sex.

3. Importance of BMI Calculation

Details: BMI-for-age is the recommended measure for screening overweight and obesity in children and teens. It's a reliable indicator of body fatness for most children.

4. Using the Calculator

Tips: Enter weight in kg, height in meters, age in years (2-20 for pediatric use), and select gender. All values must be valid (weight > 0, height > 0, age ≥ 2).

5. Frequently Asked Questions (FAQ)

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

Q2: Why use percentiles for children?
A: Children's body fat changes with age and differs between boys and girls, so BMI must be interpreted relative to growth patterns.

Q3: How accurate is BMI for children?
A: While BMI correlates with body fat, it doesn't measure body fat directly. Some muscular children may have high BMI without excess fat.

Q4: When should I be concerned about my child's BMI?
A: Consult a healthcare provider if your child is below the 5th percentile or above the 85th percentile.

Q5: Can this calculator be used for adults?
A: The calculator works for adults, but percentiles are only meaningful for children and teens (2-20 years).