Calculate your Body Mass Index with complete interpretation according to the World Health Organization.
| Underweight | < 18.5 | Moderate risk |
| Normal | 18.5 – 24.9 | Minimal risk |
| Overweight | 25 – 29.9 | Slight risk |
| Obesity I | 30 – 34.9 | Moderate risk |
| Obesity II | 35 – 39.9 | Severe risk |
| Obesity III | ≥ 40 | Very severe risk |
The Body Mass Index (BMI) is a measure that relates a person's weight to their height. It is used internationally by the World Health Organization (WHO) as a general indicator of health status in relation to body weight.
The formula is simple: BMI = Weight (kg) ÷ Height² (m). For example, a person weighing 70 kg and 1.75 m tall has a BMI of 22.9, which is considered normal.
The WHO BMI ranges apply to adults between 18 and 65 years of age. A BMI below 18.5 indicates underweight, which may be associated with nutritional deficiencies and a weakened immune system. The range between 18.5 and 24.9 is considered healthy and is associated with the lowest risk of chronic diseases. From 25 onwards, the risk begins to increase progressively: overweight between 25 and 29.9, and obesity from 30.
BMI does not distinguish between muscle mass and body fat. An athlete with a high percentage of muscle may have a BMI of 28 without having excess fat, while a sedentary person with the same BMI could present a real health risk. Additionally, BMI does not indicate how fat is distributed in the body: fat accumulated in the abdomen (visceral fat) is significantly more dangerous than fat on hips or thighs.
Maintaining a weight within the healthy range significantly reduces the risk of developing chronic diseases such as type 2 diabetes, high blood pressure, cardiovascular diseases and certain types of cancer. Studies have shown that a reduction of just 5% of body weight in overweight individuals already produces measurable improvements in blood pressure, cholesterol and insulin sensitivity.