1. What is BMI-for-age?

BMI-for-age is the measure used to assess weight status in children and teens aged 2-19 years. Unlike adults, children's BMI must be interpreted relative to other children of the same age and sex because their body composition varies as they grow.

2. How BMI is Calculated for Children

BMI is calculated the same way for children as for adults, but interpreted differently:

Key differences:

• The same BMI value means different things for different ages
• Results are compared to CDC growth charts
• Categories are expressed as percentiles rather than fixed numbers

3. Importance of BMI-for-age

Details: BMI-for-age is the recommended screening tool for overweight and obesity in children. Tracking BMI over time can show whether a child is gaining weight too slowly or too quickly compared to their height growth.

4. Using the Calculator

Tips:

• Measure weight in kilograms (accurate to 0.1 kg)
• Measure height in meters (accurate to 0.01 m)
• Enter exact age (2-19 years)
• Select the child's biological sex

5. Frequently Asked Questions (FAQ)

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

Q2: Why can't I use adult BMI categories for children?
A: Children's body fat changes with growth and differs between boys and girls, so adult categories don't apply.

Q3: How often should children's BMI be checked?
A: CDC recommends annual screening for children aged 2-19 years.

Q4: What if my child's BMI seems high?
A: Consult a healthcare provider who can evaluate growth trends and consider other factors like muscle mass.

Q5: Are there limitations to BMI-for-age?
A: BMI doesn't distinguish between fat and muscle mass, so athletic children may have high BMI without excess fat.