Body Mass Index (BMI) is a person's weight in kilograms divided by the square of height in meters. BMI screens for weight categories that may lead to health problems, but it doesn't diagnose body fatness or health.
Underweight: BMI less than 18.5
Normal weight: BMI 18.5 to 24.9
Overweight: BMI 25 to 29.9
Obese: BMI 30 or greater
Note: BMI may not be accurate for athletes, pregnant women, or the elderly.