Body Mass Index (BMI)

Body Mass Index (BMI) is a measure that adjusts bodyweight for height and has become an important standard in medicine and other professions to define the concepts of healthy, underweight, and particularly overweight and obesity. It is calculated as weight in kilograms divided by height in meters squared.

Children and Teens

For children and teens, BMI ranges above a normal weight have different labels (at risk of overweight and overweight). Additionally, BMI ranges for children and teens are defined so that they take into account normal differences in body fat between boys and girls and differences in body fat at various ages. The BMI are computed and are then compared to like aged and sex individuals from the 2000 CDC Growth Charts for females and males.

• Underweight   -   BMI-for-age less than 5th percentile

• Normal   -   BMI-for-age 5th percentile to 85th percentile

• At risk of overweight   -   BMI-for-age 85th percentile to 95th percentile

• Overweight   -   BMI-for-age at or greater than 95th percentile

Adults

For Adults weight definitions are applied directly to raw BMI numbers.

• Underweight   -   BMI less than 18.8

• Healthy Weight   -   BMI of 18.5 to less than 25

• Overweight   -   BMI greater than or equal to 25

• Obese   -   BMI greater than or equal to 30.

Body Mass Index Calculator