BMI Calculator
Free online BMI calculator — calculate your Body Mass Index using the WHO formula. Supports metric and imperial units with instant results.
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What Is BMI?
Body Mass Index (BMI) is a measure of body fat based on height and weight. It's calculated by dividing weight in kilograms by height in meters squared. The WHO classifies BMI as follows:
| Category | BMI Range |
|---|---|
| Underweight | Below 18.5 |
| Normal weight | 18.5 – 24.9 |
| Overweight | 25.0 – 29.9 |
| Obese | 30.0 and above |
BMI Formulas
Metric: BMI = weight(kg) / height(m)²
Imperial: BMI = (weight(lbs) × 703) / height(in)²
Limitations of BMI
BMI is a useful screening tool, but it doesn't account for muscle mass, bone density, age, or gender. Athletes and muscular individuals may have a high BMI without excess body fat. For a more complete picture, consider also using our Body Fat Calculator.