⚖️ BMI Calculator
Instantly calculate your Body Mass Index and find out if your weight is in a healthy range.
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What Is BMI?
Body Mass Index (BMI) is a value calculated from a person's height and weight. It is used worldwide as a quick screening tool to identify whether a person is underweight, at a healthy weight, overweight, or obese. The World Health Organization (WHO) uses BMI as a standard population-level indicator of weight-related health risk.
While BMI does not directly measure body fat, it is a simple, free, and reasonably accurate indicator for most adults. It requires only two measurements — height and weight — making it one of the most accessible health tools available.
BMI Categories — WHO Standard
| Category | BMI Range | Health Risk |
|---|---|---|
| Underweight | Below 18.5 | Risk of nutritional deficiencies |
| Normal Weight | 18.5 – 24.9 | Lowest risk range |
| Overweight | 25.0 – 29.9 | Moderate increased risk |
| Obese Class I | 30.0 – 34.9 | High health risk |
| Obese Class II | 35.0 – 39.9 | Very high health risk |
| Obese Class III | 40.0+ | Extremely high health risk |
How Is BMI Calculated?
Metric: BMI = Weight (kg) ÷ Height (m)²
Imperial: BMI = (Weight lbs × 703) ÷ Height (inches)²
Example: A person weighing 70 kg at 1.75 m height → 70 ÷ (1.75²) = 22.9 — Normal Weight.
Limitations of BMI
- Does not measure body fat directly — two people with the same BMI can have very different body compositions.
- Not suitable for athletes — muscle weighs more than fat, so muscular people may show a high BMI despite being very healthy.
- Does not account for fat distribution — abdominal fat carries more health risk than fat stored elsewhere.
- May vary by ethnicity — some populations face higher health risks at lower BMI values.
- Not for children, pregnant women, or under-18s — different assessment methods are required.
Remember: BMI is a screening tool, not a medical diagnosis. Always consult your doctor or a registered dietitian for a proper health assessment based on your full medical history.