The BMI Calculator calculates the Body Mass Index which is a measure of obesity for adult men and women. The BMI is calculated by dividing the body weight (in kilograms) by the height (in meters) squared (BMI = weight/height2). The BMI will overestimate fatness in people who are muscular or athletic, but fit persons will have a Waist-to-Height ratio less than 0.5, whereas overweight people have Waist-to-Height ratios greater than 0.5.
| 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 |
| Morbidly Obese | BMI 40 or greater |
