Category BMI range
Starving Less then 16
Underweight 16 - 18.9
Normal 19 - 25
Overweight 25.1 - 30
Obese 30.1 - 35
Clinically Obese 35.1 - 40
Morbidly Obese Over 40.1

BMI, or Body Mass Index is a measure of the relation between the weight and height of a person. It gives an index based on how much a person should weigh at a certain height. The taller a person is, the heavier he might be without being overweight. To calculate your BMI you divide your weight in kilograms by the square of your height in meters, or use the calculator. This will give you a BMI-value where 19-25 is considered normal (see table on the right.).

The BMI value has to be interpreted a bit carefully though. An athlete could have an extreme high BMI value, due to the large percentage of muscle mass in his body, this is a 'safe' overweight. Since the BMI doesn't take body fat into account it cannot solely tell if someone is dangerously overweight, but it does give a god estimate to a persons health.