What is BMI and how is it used?
Body Mass Index (BMI) is a number calculated from a person’s weight and height. It is widely used as a reliable indicator of whether a person has a healthy body weight for their height. Specifically, BMI value categorizes a person to underweight, normal weight, overweight, or obese depending on what range the value falls in.

For example, let’s calculate BMI of a 176 cm tall, 80 kg man:

This is the World Health Organization’s (WHO) recommended body weight based on BMI values for adults (men and women, > 18 years).
Category | BMI range – kg/m2 |
Severe Thinness | < 16 |
Moderate Thinness | 16 – 17 |
Mild Thinness | 17 – 18.5 |
Normal | 18.5 – 25 |
Overweight | 25 – 30 |
Obese Class I | 30 – 35 |
Obese Class II | 35 – 40 |
Obese Class III | > 40 |
BMI chart for adults
This is a graph of BMI categories based on the World Health Organization data:

Reference