Body Mass Index for Adults

What is BMI?
Body Mass Index or BMI (wt/ht²), based on an individual's height and weight, is a helpful indicator of obesity and underweight in adults.1

Determine BMI
BMI can be determined by using a hand-held calculator, looking it up on a table, or using the Web calculator.

BMI compares well to body fat but cannot be interpreted as a certain percentage of body fat. The relation between fatness and BMI is influenced by age and gender. For example, women are more likely to have a higher percent of body fat than men for the same BMI. At the same BMI, older people have more body fat than younger adults.

BMI is used to screen and monitor a population to detect risk of health or nutritional disorders. In an individual, other data must be used to determine if a high BMI is associated with increased risk of disease and death for that person. BMI alone is not diagnostic.

How does BMI relate to health among adults?

A healthy BMI for adults is between 18.5 and 24.9. BMI ranges are based on the effect body weight has on disease and death.

A high BMI is predictive of death from cardiovascular disease. Diabetes, cancer, high blood pressure and osteoarthritis are also common consequences of overweight and obesity in adults. Obesity itself is a strong risk factor for premature death.

BMI Cutpoints for Adults

We interpret BMI values for adults with one fixed number, regardless of age or sex, using the following guidelines: