BMI is calculated by dividing the weight in kilograms by the square of the height in meters. The result is expressed as kg/m².

The resulting BMI value is then interpreted according to standard ranges:

  • Underweight: BMI less than 18.5
  • Normal weight: BMI between 18.5 and 24.9
  • Overweight: BMI between 25 and 29.9
  • Obesity: BMI 30 or greater

It's important to note that while BMI is a useful screening tool, it doesn't directly measure body fat or account for factors such as muscle mass, bone density, or distribution of fat. Therefore, some individuals, such as athletes or those with a high muscle mass, may have a high BMI but a low body fat percentage. Similarly, older adults or individuals with a low muscle mass may have a normal BMI but a higher percentage of body fat.

Despite its limitations, BMI remains a widely used and valuable tool for assessing general health risks associated with weight status and is often used in healthcare settings for initial screenings and assessments. However, it should be interpreted alongside other health indicators and assessments for a comprehensive understanding of an individual's health status.