The Full form of BMI is Body Mass Index. It is a measure to classify people under the categories such as normal weight, underweight, overweight and obese. BMI is a key index for relating weight to height. It is the ratio of a man’s weight in kilograms to the square of his height in meters. People with high BMI have too much body fat or body weight for their height. BMI gives a rough estimate of a man’s overall fitness and possibility of developing chronic diseases like high blood pressure, heart disease, osteoarthritis, type 2 diabetes, gallstones etc. A highly muscular person may have a high BMI without any health risk. To calculate BMI, you are required to have two values: a person’s weight in kilograms and his height in meters. Weight should be in pounds if the height is in inches. The formula to calculate BMI is as: BMI = weight in kilograms / (height in meters) 2. Let us see an example: If a person with height 2 meters and weight 76 Kg, he will have BMI equals to 20, calculated as: BMI = 76 kg / (2)2 meter = 76 / 4 = 19 (normal weight).