Body Mass Index (BMI) is a number calculated from a person’s weight and height. BMI provides a reliable indicator of body fatness for most people and is used to screen for weight categories that may lead to health problems.
BMI can be used to indicate if you are overweight, obese, underweight or normal. A healthy BMI score is between 20 and 25. A score below 20 indicates that you may be underweight; a value above 25 indicates that you may be overweight.
BMI is a measurement of body fat based on height and weight that applies to both men and women between the ages of 18 and 65 years.
You can calculate your BMI by using the CDC calculator used below:
For children and young adults a different calculator needs to be used:
Please remember, however, that this is only one of many possible ways to assess your weight. If you have any concerns about your weight, please discuss them with your physician, who is in a position, unlike this BMI calculator, to address your specific individual situation.
BMI: Healthy Range
Once you have your BMI, find out where you fit in the BMI range. The BMI ranges indicate whether a person is underweight, normal weight, overweight (weighing more than a healthy amount), obese (more overweight), or morbidly (dangerously) obese.
• If your BMI is less than 18.5, you are underweight.
• If your BMI is between 18.5 and 24.9, you are normal weight.
• If your BMI is between 25 and 29.9, you are overweight.
• If your BMI is between 30 and 39.9, you are obese (more overweight).
• If your BMI is 40 or over, you are dangerously obese.
Note that the BMI ranges for children are different, and it’s important to ask your child’s doctor about the BMI for their age.
If you fall into any category other than normal weight, even “underweight,” it’s time to talk to your doctor about improving your eating habits to reach a healthy weight, whether that is by counting calories, changing the content of your diet, or trying another weight control method.
While most people with BMI in the overweight, obese, or morbidly obese ranges have extra body fat, there are exceptions. Some athletes, such as bodybuilders, are actually heavy because of their muscle mass, not body fat. So the meaning of BMI may be different for those people.