BMI Calculator
Calculate your Body Mass Index to understand your weight category.
Your BMI Result
What Is BMI?
Body Mass Index (BMI) is a simple numerical measure that uses your height and weight to estimate whether you are at a healthy weight. Developed by Belgian mathematician Adolphe Quetelet in the 1830s, BMI has become one of the most widely used screening tools for weight categories in healthcare. The formula is straightforward: BMI = weight (kg) / height (m)². For imperial measurements, the formula is adjusted to BMI = (weight in pounds / height in inches²) × 703.
BMI Categories and What They Mean
The World Health Organization (WHO) and the National Institutes of Health (NIH) classify BMI into four main categories: Underweight (BMI below 18.5), Normal weight (BMI 18.5–24.9), Overweight (BMI 25.0–29.9), and Obese (BMI 30.0 and above). These categories help healthcare providers identify potential health risks associated with being underweight or overweight.
While BMI is a useful screening tool, it has important limitations. It does not distinguish between muscle mass, bone density, fat distribution, or overall body composition. Athletes and bodybuilders, for example, may have a high BMI due to increased muscle mass while being in excellent physical health. Similarly, older adults may have a "normal" BMI but carry excess body fat due to age-related muscle loss. For a complete health assessment, consult with a healthcare professional who can consider additional factors such as waist circumference, diet, physical activity level, and blood work.