A person's BMI, or body mass index, is based on height and weight. It's often used to determine if a person is underweight, normal weight, overweight, or obese. But BMI doesn't consider muscle mass. Follow the links below to find WebMD's comprehensive coverage about how BMI is calculated, what it means, how to measure it with our innovative BMI Plus Calculator tool, and much more.
What Is Body Mass Index?
Learn how to use body mass index (BMI) to determine whether you are overweight.
Health Risks of Obesity
Being overweight or obese puts you at risk for many serious health conditions, including diabetes, sleep apnea, and even cancer. Learn more from WebMD about diseases you can prevent by losing weight.
Obesity and When to Seek Help
WebMD explains obesity and how to take steps to lose weight.
BMI for Kids: What Every Parent Should Know
Your child's BMI can clue you in to a weight problem - and help you make lifestyle changes that will keep your family healthier.
Need to Lose Weight? Questions to Ask Your Doctor
When you're setting out to lose weight, your doctors can help. But they may not talk about it much until you bring it up. Use these questions to start the conversation.
BMI, Waist Size, and Other Ways to See if You're Overweight
Read about BMI, waist size, and other measurements -- and why some fall short in gauging obesity.
How Accurate Is Body Mass Index, or BMI?
Is BMI still the best way to measure fatness? Some experts aren't so sure.
Jean's Story: Ice Hockey and a Healthy BMI
A woman's true story on weight loss success.