What is BMI?

Body Mass Index (BMI) is a numerical value derived from an individual’s weight and height, used as a screening tool to categorize a person’s body weight relative to their height. It helps to identify whether an individual has a healthy body weight, is underweight, overweight, or obese.

How BMI is Calculated:

The formula for BMI is:  

Alternatively, in pounds and inches:  

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BMI Categories:

• Underweight: BMI < 18.5
• Normal weight: BMI 18.5–24.9
• Overweight: BMI 25–29.9
• Obesity: BMI ≥ 30

Uses and Limitations:

• Uses:
  • It is a simple, quick, and inexpensive method to assess body fatness and categorize weight status.
  • Helps in identifying individuals who may be at risk of health problems due to their weight.
• Limitations:
  • Does not differentiate between muscle and fat mass, which can lead to misclassification in athletes or muscular individuals.
  • Does not account for age, sex, or fat distribution.
  • May not be accurate for all ethnic groups or for children and the elderly.

Despite its limitations, BMI is widely used as a general indicator of health related to body weight