Body Mass Index

Body Mass Index is calculated by dividing an individual's weight in pounds (or kilograms) by his or her height in inches (or meters) squared. This measurement is used for assessing whether a person has a healthy amount of adiposity (body fat) and tracks obesity.

Body Mass Index ranges from 18.5 to 40 (under 18.5 being underweight, between 19 and 25 normal, over 30 overweight and over 35 obese). To determine BMI, a person must enter his or her height and weight information into a Body Mass Index calculator.

Although the system is an effective means of determining normal body mass, the index does not take into account muscle mass or body type. A weight lifter and an obese person may have the same BMI, for example. Body Mass Index charts are nonetheless useful for monitoring child obesity.