BMI for Teens

Body Mass Index (BMI) for teens is used differently than BMI for adults. While the calculation is the same, the interpretation depends on age and biological sex because teenagers are still growing and developing.

If you want to calculate BMI using height and weight, you can use our BMI calculator. Just keep in mind that teen results should be interpreted using percentiles, not adult BMI categories.

How BMI for teens is different

For adults, BMI is compared to fixed number ranges. For teens and children, BMI is compared to others of the same age and sex using percentiles.

These percentiles show how a teen’s BMI compares to a reference population:

• Underweight: below the 5th percentile
• Healthy weight: 5th to less than the 85th percentile
• Overweight: 85th to less than the 95th percentile
• Obesity: 95th percentile or higher

Why percentiles matter for teenagers

During adolescence, body composition changes rapidly. Growth spurts, puberty, and hormonal changes all affect weight and height at different rates.

Because of this, a BMI number alone does not give the full picture for teens. Percentiles help account for normal growth patterns.

Using BMI wisely for teens

BMI for teens is best used as a screening tool, not a diagnosis. If a teen’s BMI percentile is high or low, it does not automatically mean there is a health problem.

Other important factors include:

• Overall growth pattern
• Physical activity level
• Diet and nutrition
• Family health history

If there are concerns about growth or weight, a healthcare professional can help interpret BMI results in context.

Can teens use a BMI calculator?

A standard BMI calculator can be used to calculate the BMI number, but the result should then be compared to age- and sex-specific growth charts.

You can calculate BMI using our free BMI calculator, then discuss the result with a qualified healthcare provider if needed.