BMI Calculator
Calculate your Body Mass Index (BMI) from height and weight. Supports metric and imperial units. Instantly shows your BMI category with a visual gauge.
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Free
Browser-based
BMI Formula
BMI is calculated as weight (kg) ÷ height² (m²). For imperial: (weight in lb × 703) ÷ height² (in²). The result is a dimensionless number used to screen for weight categories that may lead to health problems.
BMI Categories (WHO)
| BMI Range | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Normal weight |
| 25.0 – 29.9 | Overweight |
| 30.0 – 34.9 | Obese (Class I) |
| 35.0 – 39.9 | Obese (Class II) |
| 40.0 and above | Obese (Class III) |
Limitations of BMI
BMI does not distinguish between fat and muscle. Athletes with high muscle mass often appear "overweight" by BMI despite being healthy, while some people with a "normal" BMI may carry excess visceral fat. Use BMI alongside other metrics and professional guidance.