BMI Calculator

Body mass index (BMI) is calculated by dividing your weight (in kilograms) by the square of your height (in meters): BMI = weight / height². It is the most widely used indicator for quickly assessing body weight at a population level, since it only requires a scale and a tape measure.

According to World Health Organization thresholds, a BMI below 18.5 indicates underweight, between 18.5 and 24.9 normal weight, between 25 and 29.9 overweight, and 30 or above obesity.

BMI remains an approximate indicator: it does not distinguish muscle mass from fat mass, and is not always relevant for very muscular athletes, pregnant women, or older adults. It is a useful starting point, not a medical diagnosis — for accurate tracking, combine it with other measurements (waist circumference, body composition) and a professional's advice.