BMI Calculator

BMI (Body Mass Index) is a measure of body fat based on height and weight. It is calculated as weight (kg) divided by height squared (m²). For example, a person weighing 70kg at 175cm has a BMI of 70 / (1.75²) = 22.9.

According to the World Health Organization: Underweight is below 18.5, Normal weight is 18.5–24.9, Overweight is 25–29.9, and Obese is 30 or above. These categories apply to most adults aged 18–65.

BMI has limitations. It does not directly measure body fat and can misclassify muscular athletes as overweight. It may also be less accurate for older adults, children, and certain ethnic groups. Use BMI as a screening tool, not a definitive health diagnosis.

A sustainable approach combines a moderate caloric deficit (typically 500 kcal/day below maintenance) with regular physical activity (150+ minutes per week). Prioritize strength training to preserve muscle and protein intake of 1.2–1.6g per kg of body weight.

BMI estimates whether your weight is appropriate for your height using only a ratio. Body fat percentage directly measures how much of your weight is fat vs. lean mass. Body fat percentage is more accurate but requires special equipment (DEXA scan, calipers, BIA scale).