BMI Calculator

BMI is a screening tool that uses height and weight to estimate body fat. While it does not measure body fat directly, it correlates with more direct measures of body fat such as skinfold thickness and underwater weighing.

BMI categories: Underweight is below 18.5, Normal weight is 18.5–24.9, Overweight is 25.0–29.9, and Obese is 30.0 and above. These ranges apply to adults 20 years and older.

Limitations: BMI does not distinguish between muscle and fat mass. Athletes and muscular individuals may have a high BMI but low body fat. Conversely, older adults may have a normal BMI but carry excess fat. BMI also does not account for bone density, race, or sex differences.

When to consult a doctor: BMI is a starting point, not a diagnosis. If your BMI falls outside the normal range, speak with a healthcare provider for a comprehensive assessment including waist circumference, diet, physical activity, and family history.