AixKit
All-in-One Online Calculators
AixKit
All-in-One Online Calculators
Enter the details below to calculate BMI for a child or teenager. BMI is calculated as Weight (kg) / [Height (m)]².
Body Mass Index (BMI) is a widely used method to assess whether an individual is within a healthy weight range. For adults, BMI interpretation is straightforward. However, for children and teens (ages 2–19), it’s more complex and requires comparison against standardized growth charts that factor in age and sex. That’s where a BMI Calculator for Child and Teen becomes essential.
This guide provides a comprehensive explanation of what BMI means for youth, how to calculate and interpret it, and how to use this tool responsibly. Whether you are a parent, teacher, coach, or healthcare professional, understanding BMI can help track healthy growth and development.
BMI is a ratio of weight to height that estimates body fat. The formula is the same for everyone:
BMI = weight (kg) ÷ height (m²)
Or in imperial units:
BMI = (weight in pounds ÷ height in inches²) × 703
For children and teens, BMI is plotted on the Centers for Disease Control and Prevention (CDC) growth charts, and then converted to a percentile that compares a child’s BMI to others of the same age and sex.
Children are constantly growing and developing. Their bodies change in ways that vary dramatically by age and gender. Unlike adults, who have static BMI categories, children’s BMIs must be interpreted using percentiles.
Because of this, BMI-for-age percentiles are the gold standard for assessing a child or teen’s growth pattern.
Monitoring BMI in children and teens helps identify potential weight-related health issues early. Early detection can prevent chronic conditions later in life.
While BMI is a useful screening tool, it has limitations. It does not directly measure body fat or distinguish between fat and muscle mass. Therefore, it should always be interpreted in context.
Always consult a pediatrician or healthcare provider for a full health evaluation.
The calculator uses CDC or WHO growth charts, depending on the user’s region or preference.
Let’s say a 10-year-old girl weighs 70 pounds and is 55 inches tall:
BMI = (70 ÷ (55 × 55)) × 703 = 22.7
This BMI is then plotted on the CDC chart for girls age 10.
If the 22.7 BMI falls in the 92nd percentile, she is categorized as overweight.
If your child is outside the healthy weight range, don’t panic. BMI is a starting point for discussion, not a diagnosis.
Growth charts show where your child stands compared to others of the same age and sex. Each percentile indicates the percentage of peers with a lower BMI.
These charts are updated and maintained by the CDC in the U.S. and WHO globally.
Always seek clinical input before drawing conclusions from a BMI percentile.
No. BMI percentiles are gender-specific because growth patterns differ by sex.
Generally, the 5th to 85th percentile is considered healthy.
Yes. Some naturally thin or athletic children may fall outside normal percentiles and still be healthy.
Once or twice a year during well-child visits is typically sufficient unless advised otherwise.
No. Instead, focus on healthy habits and consult a healthcare professional.
The BMI Calculator for Children and Teens is a valuable tool for assessing weight-related growth trends. It helps identify early signs of underweight, overweight, or obesity, and promotes early intervention and healthier choices.
However, it’s not a definitive measure of health. Always interpret BMI results alongside other health markers such as energy levels, physical activity, diet, mental health, and family history.
A healthy childhood lays the foundation for lifelong wellbeing. Use this calculator to track, understand, and support your child’s journey toward balanced growth and a healthy future.