About Body Mass Index (BMI)
Body Mass Index (BMI) is a simple index of weight-for-height that is commonly used to classify underweight, overweight and obesity in adults. It is defined as the weight in kilograms divided by the square of the height in metres (kg/m2). The equations used to calculate BMI are as follows:
- BMI (metric) = mass (kg)/(height (m))2
- BMI (imperial) = (mass (lb)/(height (in))2) x 703.06957964
BMI results are classified under the following categories:
- Underweight – <18.50
- Normal – 18.5 to 24.99
- Overweight – 25.00 to 29.99
- Obese – 30.00 to 39.99
- Morbidly Obese – >40.00
For more accurate results (as it relates to your BMI score), click here to access the corresponding standardized BMI chart.
BMI may not apply to some individuals with more than normal muscle mass and acceptable levels of body fat. In some ethnic groups, such as Pacific Islanders, BMI overestimates fatness and risk. For children and the elderly, BMI may be misleading since the muscle and bone to height relationship is constantly changing.
Some scientists believe that body mass index is an inaccurate measure of obesity-related risks because it does not account for body shape, fat mass and lean mass. But new studies find that BMI works at least as well as other body measurements, and better than some, to predict certain health problems.
Additional BMI Calculators
Other BMI calculators can be accessed using the following links: