BMI Calculator

This BMI calculator uses a standardized metric-based formula to calculate your Body Mass Index, regardless of the unit system you select. The calculator converts all inputs to metric units before performing the calculation to ensure consistent and accurate results.

The BMI Formula

This formula is recommended by the World Health Organization (WHO) and is the international standard for BMI calculation.

Conversion Process

When using imperial units:

• Height conversion: Feet and inches are converted to meters (1 foot = 0.3048 meters, 1 inch = 0.0254 meters)
• Weight conversion: Pounds are converted to kilograms (1 pound = 0.453592 kg)

The calculator then uses the metric formula shown above to compute your BMI.

International BMI Categories

BMI values are categorized according to WHO standards:

BMI Range	Category	Health Risk
Below 18.5	Underweight	Possible nutritional deficiency, osteoporosis
18.5 - 24.9	Normal weight	Lowest health risk
25.0 - 29.9	Overweight	Increased risk of health problems
30.0 and above	Obese	High risk of serious health conditions

Important Considerations

While BMI is a useful screening tool, it has some limitations:

• BMI doesn't distinguish between muscle and fat mass
• Athletes may have a high BMI due to muscle mass rather than excess fat
• BMI may underestimate body fat in older adults who have lost muscle mass
• Ethnicity can affect health risks at different BMI levels
• BMI doesn't account for body fat distribution

For a comprehensive health assessment, consult with a healthcare professional who can consider additional factors like waist circumference, diet, physical activity, and family history.