Body Mass Index (BMI) Calculator

Body mass index (BMI) is a measure of body fat based on height and weight that applies to both adult men and women. BMI is recognized by the National Institutes of Health (NIH) and The World Health Organization as the best standard to judge obesity. BMI is also one of the most accurate and widely used measurements to determine if extra pounds pose health risks.

Body Mass Index (BMI)

Sex
Height
Weight

BMI
Population Average
Classification

According to the National Institute of Health (NIH), your BMI score means the following:

  • Underweight: below 18.5
  • Normal: 18.5 to 24.9
  • Overweight: 25 to 29.9
  • Obese: 30 to 39.9
  • Extremely obese: 40 and above

While BMI is accurate for most people, it doesn't work for everyone. It's important to remember that:

  • You could have a high BMI but be at a weight that is considered healthy if you're muscular or athletic.
  • You could have a normal BMI and have poor nutrition.
  • It's important to talk to your doctor about weight-related health risks.

 

Classification of Overweight and Obesity by BMI, Waist Circumference,
and Associated Disease Risks

Disease Risk* Relative to Normal Weight and Waist Circumference
BMI
Obesity
Class
Men 102 cm (40 in) or less
Women 88 cm (35 in) or less
Men > 102 cm (40 in)
Women > 88 cm (35 in
Underweight
< 18.5
Normal
18.5 - 24.9
Overweight
25.0 - 29.9
Increased
High
Obesity
30.0 - 34.9
I
High
Very High
35.0 - 39.9
II
Very High
Very High
Extreme Obesity
40.0 +
III
Extremely High
Extremely High

* This table is from the National Heart Lung and Blood Institute