BMI Calculator
Calculate Body Mass Index (BMI), WHO weight category, and healthy target weight range with Metric or Imperial units. 100% in-browser.
Ideal healthy weight range with lowest statistical cardiovascular risks.
World Health Organization (WHO) BMI Standards
| Classification | BMI Range (kg/m²) | BMI Prime | Health Risk Level |
|---|---|---|---|
| Severe Underweight | < 16.0 | < 0.64 | Increased risk of nutritional deficiency |
| Underweight | 16.0 - 18.4 | 0.64 - 0.74 | Mild to moderate nutritional deficiency |
| Normal Weight | 18.5 - 24.9 | 0.74 - 1.00 | Lowest cardiovascular and metabolic risk |
| Overweight | 25.0 - 29.9 | 1.00 - 1.20 | Moderate risk of lifestyle disease |
| Obesity Class I | 30.0 - 34.9 | 1.20 - 1.40 | High clinical risk |
| Obesity Class II | 35.0 - 39.9 | 1.40 - 1.60 | Very high clinical risk |
| Obesity Class III | ≥ 40.0 | ≥ 1.60 | Extremely high clinical risk |
Interpreting Body Mass Index Metrics
BMI calculates gross mass per surface area and cannot differentiate between dense skeletal muscle and adipose tissue. Athletes and bodybuilders frequently register as overweight despite low body fat.
BMI Prime normalizes your score against the WHO upper normal cutoff (25.0). A score under 1.00 is within normal parameters; a score of 1.16 indicates body weight is 16% above upper normal boundary.
By dividing body weight by height cubed (kg/m³), the Ponderal Index offers better allometric scaling for exceptionally tall (>190 cm) or petite adults where square scaling skews standard BMI.
For individuals aged 65 and older, observational health research suggests that a slightly higher BMI range (23 to 28) correlates with improved mortality outcomes and bone mineral retention.
About This Tool
The Body Mass Index (BMI) Calculator provides a quick assessment of body weight relative to height based on World Health Organization (WHO) and CDC clinical standards.
Easily toggle between Metric (centimeters and kilograms) and Imperial (feet, inches, and pounds) measurement units. The tool determines your exact BMI, Prime ratio, Ponderal index, and calculates your personalized ideal healthy weight boundaries.
Key Features
- Metric and Imperial dual modes: Input height in centimeters or feet and inches, and weight in kilograms or pounds with live synchronized conversion.
- Visual BMI gauge spectrum: Interactive multi-tier color spectrum illustrates where your body mass index falls across clinical categories.
- Ideal healthy weight range: Computes the exact minimum and maximum healthy weights for your specific height based on BMI 18.5 to 24.9.
- Advanced metrics: Includes BMI Prime (ratio against upper normal 25.0 limit) and Ponderal Index for taller or shorter physiques.
- 100% private in-browser: All health metrics are calculated locally inside your browser memory. Nothing is tracked, logged, or uploaded.
