BMI Calculator

Body Mass Index is calculated using the formula BMI = weight (kg) / height (m)². This formula, developed by Adolphe Quetelet in the 19th century, is the internationally recognized standard (WHO).

According to the WHO, the normal range is 18.5 to 24.9 kg/m². In this range, the statistical risk for weight-related diseases is the lowest.

By WHO criteria, overweight starts at a BMI of 25.0. From 30.0 onward, the classification becomes obesity, divided into three severity classes.

Only to a limited degree. BMI does not distinguish between muscle and fat mass. Athletes with high muscle mass may show a BMI in the overweight range without being overfat.

Children are assessed using age- and sex-specific percentiles rather than fixed BMI cutoffs. For seniors over 65, the healthy range shifts slightly upward (24–29 kg/m²) per recent guidelines.

BMI ignores body fat distribution, muscle ratio, sex, and ethnicity. Complementary measures like waist circumference or body-fat percentage give a fuller picture.