Calculate your Body Mass Index using metric (kg/cm) or imperial (lbs/ft) measurements. Includes BMI category, healthy weight range, and scale visualization.
Runs in your browser · No data stored anywhereBMI is a screening tool, not a diagnostic measure. It does not account for age, sex, muscle mass, or ethnicity. Consult a healthcare professional for personal health advice.
Body Mass Index (BMI) is a measure of body fat based on height and weight. It's calculated as weight (kg) divided by height squared (m²). For example: 70 kg / (1.75 m)² = 22.9.
Underweight: under 18.5 · Normal weight: 18.5–24.9 · Overweight: 25–29.9 · Obese Class I: 30–34.9 · Obese Class II: 35–39.9 · Obese Class III: 40+. These are WHO classifications for adults.
BMI is a useful population-level screening tool but has significant limitations for individuals. It doesn't distinguish muscle from fat, so athletes often have a "high" BMI despite being healthy. It's also less accurate for elderly people and different ethnic groups.
Metric: BMI = kg / m². Imperial: BMI = (lbs / in²) × 703. For a 70 kg person who is 175 cm tall: 70 / (1.75)² = 70 / 3.0625 ≈ 22.9.