BMI is calculated by dividing weight in kilograms by the square of height in meters. The resulting number is used to categorize people into different weight groups:
Below 18.5: Underweight
18.5–24.9: Normal weight
25.0–29.9: Overweight
30.0 and Above: Obese
BMI is not a perfect measure of body fat, but it is a simple and inexpensive tool that can be used to screen for weight-related health problems.