BMI Calculator — Calculate Body Mass Index (Metric & Imperial)

Body Mass Index (BMI) is a standardized screening metric established by the World Health Organization (WHO) to categorize body mass based on height and weight. Pexlii calculates your BMI locally on your device without sending any personal health or body measurements across the internet. When you select the Metric tab, the tool uses the standard formula: weight in kilograms divided by the square of height in meters (kg/m²). When you select the Imperial tab, your height in feet and inches is converted to total inches and multiplied by the standard imperial conversion factor of 703: (weight in lbs / height in inches²) × 703. The calculator maps your result to official WHO weight classifications: Underweight (< 18.5), Normal Weight (18.5–24.9), Overweight (25–29.9), and Obesity (30+). It also computes your personalized healthy weight range based on your exact height. Every calculation happens instantly in your browser memory, ensuring complete confidentiality for your personal health numbers.