# What is body mass index (BMI) and how do you calculate it?

Body mass index, or BMI, is a way of describing height and weight in one number that can help tell if someone's weight is healthy.

To figure out your BMI, just use this math formula: Multiply your weight in pounds by 703 and divide it by your height (in inches) squared.

Obesity in adults is defined as having a BMI of 30.0 or above. The other ranges are:

• Overweight = 25.0 to 29.9
• Normal weight = 18.5 to 24.9
• Underweight = under 18.5

SOURCES:

CDC: “Healthy Weight.”

National Institutes of Health: “Aim for a Healthy Weight.”

Cleveland Clinic: “Weight Management and Obesity,” “Weight Control and Obesity FAQ.”

Mayo Clinic: “Obesity.”

Reviewed by Melinda Ratini on June 18, 2019

SOURCES:

CDC: “Healthy Weight.”

National Institutes of Health: “Aim for a Healthy Weight.”

Cleveland Clinic: “Weight Management and Obesity,” “Weight Control and Obesity FAQ.”

Mayo Clinic: “Obesity.”

Reviewed by Melinda Ratini on June 18, 2019

#### NEXT QUESTION:

Can measuring my waist help me know if I am a healthy weight?