Definition

Understanding Body Mass Index (BMI)

Choose a preferred language

Body mass index (BMI) is a way to figure out your weight category. It uses the ratio of your height to your weight. 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, 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 


Use an online tool

Go online and search for BMI calculators. Try the Centers for Disease Control and Prevention (CDC) website. Or go to the American Cancer Society website. Both have online BMI tools.


Using the BMI chart

To figure out your BMI, find your height and weight (or the numbers closest to them) on the table below. Follow each column of numbers to where your height and weight meet on the table. That is your BMI.

Body Mass Index table showing BMI numbers for height and weight.

Featured in

Online Medical Reviewer: Raymond Turley Jr PA-C

Online Medical Reviewer: Sravani Chintapalli Researcher

Date Last Reviewed: 04/01/2025

© 2000-2026 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.

Find a Provider

View Our Directory

Find a Location

View Our Practices
Related Articles
Read article
Orthopedics
When Your Child Needs Surgery: Anesthesia

During surgery, your child will receive anesthesia. This is medicine that causes your child to relax or fall asleep, and not feel pain during surgery. See below for more information about different types of anesthesia.

Read article
Digestive Health
Introduction to Bariatric Surgery

Understand that bariatric surgery may be an option for some people and how it may be determined if someone is a candidate for bariatric surgery.

Read article
Digestive Health
Obesity and Its Impact on Health

Obesity can increase your risk for many serious health issues. These include problems with your heart, lungs, blood vessels, brain, and joints.

Read article
Ear, Nose, and Throat
Tonsil, Adenoid, and Ear Tube Surgery: Going to Surgery

Your child will be cared for by a surgical team. This team will include a surgeon, and one or more nurses, and other health professionals. An anesthesiologist or nurse anesthetist will give your child medicine to make him or her fall asleep. Here is information about your child's surgery.