Calculate your Body Mass Index (BMI) from your height and weight in either metric or imperial units. BMI is a quick screening number that estimates whether your weight is in a healthy range for your height, and it is widely used as a first-pass health indicator. This calculator shows your exact BMI value plus the standard category (underweight, normal, overweight or obese) using the World Health Organization thresholds. Remember that BMI does not account for muscle mass or body composition, so athletes may read high; treat it as a rough guide, not a diagnosis. Enter your numbers and the result updates instantly, all computed locally in your browser.