Overview

Body mass index (BMI) can help you see if your weight is raising your risk for health problems. It uses a formula to compare how much you weigh with how tall you are.

• A BMI lower than 18.5 is considered underweight.
• A BMI between 18.5 and 24.9 is considered healthy.
• A BMI between 25 and 29.9 is considered overweight. A BMI of 30 or higher is considered obese.

If your BMI is in the normal range, it means that you have a lower risk for weight-related health problems. If your BMI is in the overweight or obese range, you may be at increased risk for weight-related health problems, such as high blood pressure, heart disease, stroke, arthritis or joint pain, and diabetes. If your BMI is in the underweight range, you may be at increased risk for health problems such as fatigue, lower protection (immunity) against illness, muscle loss, bone loss, hair loss, and hormone problems.

BMI is just one measure of your risk for weight-related health problems. You may be at higher risk for health problems if you are not active, you eat an unhealthy diet, or you drink too much alcohol or use tobacco products.