Body Mass Index (BMI): Understand & Calculate
Body mass index (BMI) is a way to figure out your weight category. It uses the ratio of your height to your weight. The BMI is a measure of your weight that is corrected for height. Knowing your BMI is a way to tell if you are at a healthy weight, are underweight, or overweight. The higher your BMI, the greater your risk for weight-related health problems.
What BMI means for adults
- BMI below 18.5: Underweight
- BMI 18.5 to 24.9: Healthy weight or ideal body weight
- BMI 25 to 29.9: Overweight
- BMI 30 and over: Obese
- BMI 40 and over: Severe obesity
Using the BMI chart
To calculate your body mass index, find your height and weight (or the numbers closest to them) on the body mass index chart below. Follow each column of numbers to where your height and weight meet on the table. That is your BMI.