Calculate your Body Mass Index (BMI), identify weight categories, and discover your healthy weight range in metric or imperial units.
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A Body Mass Index (BMI) calculator estimates body fatness based on an individual's weight and height. Established by Belgian statistician Adolphe Quetelet, BMI is utilized worldwide by the World Health Organization (WHO) and Centers for Disease Control and Prevention (CDC) as an initial health screening metric.
\text{Metric: } \text{BMI} = \frac{\text{weight (kg)}}{[\text{height (m)}]^2} \quad \text{Imperial: } \text{BMI} = \frac{703 \times \text{weight (lbs)}}{[\text{height (in)}]^2}Divide body weight by height squared. For imperial measurements, multiply weight in pounds by 703 before dividing by height in inches squared.
Scenario: An adult weighs 70 kg and is 175 cm (1.75 m) tall.
Square height in meters: 1.75 × 1.75 = 3.0625 m².
Divide weight by height squared: 70 / 3.0625 = 22.86.
Compare with WHO criteria (18.5 – 24.9 is Normal Weight).
According to the WHO: Underweight (< 18.5), Normal Weight (18.5–24.9), Overweight (25.0–29.9), Obesity Class I (30.0–34.9), Obesity Class II (35.0–39.9), and Obesity Class III (≥ 40.0).
For children and adolescents aged 2 to 19, BMI is assessed using age-and-sex-specific growth chart percentiles rather than fixed adult thresholds.
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56.7 – 76.3 kg