Biometric Details
BMI Calculator — Free Body Mass Index & Weight Range | Cruse
Calculate your exact Body Mass Index (BMI) instantly in Metric (cm, kg) or Imperial (ft, lbs). Features WHO health classifications, healthy weight ranges, and visual spectrum gauge.
How to Use This Tool
Select Measurement System
Choose Metric (centimeters & kilograms) or Imperial (feet, inches & pounds) according to your preference.
Input Your Personal Metrics
Enter your age, sex, height, and body weight. You can type numbers directly into the fields or adjust the smooth sliders.
Analyze Your Health Spectrum
View your real-time BMI score on the color-coded WHO spectrum gauge, review your healthy weight target range, and copy your results.
Technical Reference & Specifications
| Parameter / Standard | Specification |
|---|---|
| Classification Standard | World Health Organization (WHO) International Adult BMI Classifications |
| Calculated Parameters | BMI (kg/m²), Healthy Weight Range, Weight Delta to Normal, Ponderal Index (kg/m³) |
| Measurement Systems | Dual Mode: Metric (cm, kg) and US Imperial (ft, in, lbs) |
| Underweight Threshold | BMI < 18.5 kg/m² |
| Normal / Healthy Range | BMI 18.5 – 24.9 kg/m² |
| Overweight Threshold | BMI 25.0 – 29.9 kg/m² |
| Obese Thresholds | Class I: 30.0–34.9 | Class II: 35.0–39.9 | Class III: ≥ 40.0 kg/m² |
| Client Privacy | 100% In-Browser. No biometric or personal health data is ever transmitted or logged. |
Frequently Asked Questions
What is Body Mass Index (BMI) and how is it calculated?
Body Mass Index (BMI) is an internationally recognized screening metric used by the WHO and CDC to classify human weight categories. In Metric, the formula is: BMI = Weight (kg) / [Height (m)]². In US Imperial, the formula is: BMI = [Weight (lbs) × 703] / [Height (inches)]².
Does BMI distinguish between muscle mass and body fat?
No. BMI is an epidemiological screening tool based on total body weight rather than body composition. Highly muscular athletes, bodybuilders, and pregnant individuals may record an "overweight" or "obese" BMI despite having low body fat and excellent cardiovascular fitness.
What is a healthy BMI range for adults?
According to the World Health Organization (WHO), a healthy BMI for adult men and women is between 18.5 and 24.9 kg/m². Values below 18.5 suggest underweight, while 25.0 to 29.9 indicates overweight, and 30.0 or higher indicates obesity.
What is the Ponderal Index (PI)?
The Ponderal Index (or Corpulence Index) is calculated as Weight (kg) / [Height (m)]³. Unlike BMI, which scales height by a square factor (2D), the Ponderal Index scales height cubically (3D), providing a more proportional evaluation for very tall or very short individuals.
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