BMI: What Your Number Means

The body mass index (BMI) is a tool you can use to know whether your weight is healthy. It's based on a ratio of your height and weight.

Generally, a BMI below 18.5 means you're underweight. A BMI within 18.5 and 24.9 is considered normal weight, while a BMI that falls between 25 - 29.9 means you're overweight. If your number is 30 or higher, you're considered obese.

Having a high BMI increases your risk for serious health problems, from diabetes to heart disease. People who are overweight or obese have a greater chance of developing certain cancers—including breast cancer for women past menopause, and colorectal cancer—as well as high blood pressure, high blood cholesterol, and stroke.

However, as with any tool, it isn't perfect. The BMI may not be accurate for athletes with greater muscle mass or older adults with less, for example. It also doesn't take into account other indicators of health, such as waist size, cholesterol, and blood sugar levels.

To find out your BMI, enter your height and weight in our BMI calculator.

Body Mass Index (BMI) Calculator

Enter your height and weight below to find your body mass index (BMI).This number is commonly used to judge whether your weight is healthy—or whether extra weight increases your risk for health problems, such as cancer.

Calculate Your BMI

Height: feet and inch(es)

Weight: lbs

Your BMI:

What the Numbers Mean

Below 18.5	Underweight
18.5-24.9	Normal weight
25-29.9	Overweight
30 and higher	Obese

Note: The BMI may not be accurate for people with greater muscle mass (such as athletes) or in older people and others who have lost muscle mass.

A doctor can further assess your personal risk for serious weight-related diseases by considering your BMI, waist size, and other measures of health such as blood sugar levels.

Even a small weight loss (10% of your current weight) lowers the risk of several diseases. People who are overweight or obese have a greater chance of developing certain cancers—including breast cancer for women over age 50—as well as high blood pressure, high blood cholesterol or other lipid disorders, diabetes, heart disease, and stroke.

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