The Body Mass Index (BMI) is a stastical measure of weight ranges. BMI is calculated by dividing your weight by your height. You shouldn't use BMI as a diagnosis - it's intended to give you an idea of how heavy you are relative to other people of your height. Try our BMI calculator to see if your weight falls within a healthy range. A BMI of under 18.5 suggests that you may be underweight. This may be symptomatic of an underlying condition which may require medical attention. BMI is an approximate measure based on statistical trends - you could very well be perfectly healthy. Talk to your doctor for more advice. A BMI between 18.5 and 25 suggests your weight is at a healthy level. This does not mean that you need not worry about cholesterol, cardiovascular disease, and other health problems associated with weight. For a more accurate assesment, see your doctor. BMI results between 25 to 30 are in the overweight range. You may be at greater risk of obesity-related conditions, such as diabetes and cardiovascular disease. BMI is simply a statistical average, and should not be considered an authoritative assessment of your health. See your doctor if you have any concerns. A BMI above 30 may mean that you are obese, and have an unhealthy proportion of body fat. BMI results are based on statistical trends, and in your case may not be accurate (particularly if you have high muscle or bone mass). See your doctor if you have any concerns.