Body Mass Index Calculator
Body Mass Index (BMI) is a simple ratio of your weight to your height squared. Despite being over 190 years old, it remains the most widely used screening tool for weight-related health risk by the WHO, CDC, NHS, and healthcare providers worldwide. Enter your measurements below to get your BMI instantly — with a visual gauge, category classification, and your healthy weight range.
BMI Calculator
Enter your height and weight to calculate your Body Mass Index.
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kg
BMI Categories
WHO classification of Body Mass Index ranges.
| Category | BMI Range | Status |
|---|---|---|
Underweight | < 18.5 | May indicate nutritional deficiency |
Normal | 18.5 – 24.9 | Lowest health risk |
Overweight | 25 – 29.9 | Moderate increased risk |
Obese I | 30 – 34.9 | High risk |
Obese II | 35 – 39.9 | Very high risk |
Obese III | 40+ | Extremely high risk |
Frequently Asked Questions
- What is Body Mass Index?
- Body Mass Index (BMI) is a numerical value derived from your weight and height (kg/m^2). It provides a quick estimate of whether your weight is proportionate to your height. BMI is used as a screening tool for weight categories: underweight, normal, overweight, and obese.
- Is Body Mass Index reliable?
- BMI is reliable as a population-level screening tool but has limitations for individuals. It doesn't measure body fat directly, doesn't account for muscle mass, and doesn't consider fat distribution. Athletes, elderly people, and different ethnic groups may need additional metrics for accurate assessment.
- What are the limitations of BMI?
- BMI doesn't distinguish fat from muscle (athletes score 'overweight'), doesn't measure fat distribution (visceral fat is more dangerous than subcutaneous), doesn't account for age (body composition changes over time), and uses population-level cutoffs that may not apply to all ethnicities. Use BMI alongside other measures like waist circumference for a fuller picture.
Medical disclaimer: BMI is a screening tool, not a medical diagnosis. It does not measure body fat directly and does not account for muscle mass, bone density, age, sex, or ethnicity. Consult a healthcare provider for personalized health advice.
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