Body mass index (BMI) is a measure that estimates body fat based on height and weight. BMI is expressed in kilograms per square meter (kg/m2). For example, a person who weighs 145 pounds and is 5 feet 10 inches tall has a BMI of 23.1.
BMI is a useful tool for screening for weight-related health problems such as obesity, heart disease, and cancer. It can also be used to track changes in body weight over time.