BMI Calculator
Calculate your body mass index (BMI) using metric or imperial units. Includes the WHO category and the healthy weight range for your height.
📖 Read the guide: BMI vs body fat percentage
BMI categories (WHO, adults 20+)
| Category | BMI range |
|---|---|
| Underweight | under 18.5 |
| Healthy weight | 18.5 – 24.9 |
| Overweight | 25.0 – 29.9 |
| Obesity class I | 30.0 – 34.9 |
| Obesity class II | 35.0 – 39.9 |
| Obesity class III (severe) | 40.0 and over |
BMI formula
Metric: BMI = kg ÷ (height in meters)². Imperial: BMI = (lb × 703) ÷ (height in inches)². Both formulas produce the same value for the same person.
Limitations of BMI
BMI is a population-level screening tool, not a diagnosis. It does not distinguish muscle from fat, so very muscular people often score "overweight" despite low body fat. It also does not account for fat distribution — visceral (abdominal) fat carries more health risk than subcutaneous fat at the same total weight. Waist circumference and waist-to-height ratio capture this better. Talk to your healthcare provider for a complete assessment.
This calculator is provided for informational purposes only and is not medical advice.