Free Clinical Tool
BMI Calculator
Calculate Body Mass Index from height and weight. Supports both imperial (ft/in, lbs) and metric (cm, kg) units with instant category classification.
Body Mass Index (BMI) is one of the most widely used screening tools in clinical practice. It provides a quick, standardized way to assess whether a patient falls within a healthy weight range relative to their height. While BMI does not directly measure body fat or account for muscle mass, it remains a valuable first-pass assessment used by massage therapists, chiropractors, physical therapists, and other wellness practitioners during intake and progress evaluations. This calculator supports both imperial and metric units and provides instant BMI classification according to WHO categories.
How to Use This Calculator
Select your preferred unit system (imperial or metric). Enter the patient's height and weight. The BMI result and category will update automatically as you type. Use the color-coded result to quickly identify the BMI classification.
Formula & Method
BMI is calculated as weight in kilograms divided by height in meters squared: BMI = weight(kg) / height(m)². For imperial units, the formula is: BMI = (weight(lbs) × 703) / height(inches)². The WHO classifies BMI as: Underweight (< 18.5), Normal (18.5–24.9), Overweight (25–29.9), Obese Class I (30–34.9), Obese Class II (35–39.9), and Obese Class III (≥ 40).
Disclaimer
BMI is a screening tool, not a diagnostic measure. It does not account for muscle mass, bone density, age, sex, or ethnicity. Always use BMI alongside other clinical assessments. This calculator is for educational purposes and should not replace professional medical advice.
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