BMI Calculator
The BMI (Body Mass Index) Calculator estimates whether your weight falls in a healthy range for your height, using the same formula doctors and health organizations use as a quick screening tool.
How BMI is calculated
Body Mass Index is calculated by dividing weight by the square of height. In metric units:
In US (imperial) units, the formula includes a conversion factor of 703:
BMI categories
The World Health Organization defines four standard adult BMI categories: below 18.5 is Underweight, 18.5–24.9 is Healthy Weight, 25–29.9 is Overweight, and 30 or above is Obesity.
Limitations of BMI
BMI is a fast screening tool, not a diagnostic measure. It doesn't distinguish between muscle and fat, so very muscular people can show a high BMI despite low body fat, and it may not account for age, sex, or body composition differences. For a more detailed picture, try our Body Fat Calculator alongside this one.