Body Mass Index (BMI) Calculator
Calculate your personal BMI, view your category on the spectrum, and determine your healthy weight range.
Formula Used: BMI = Weight (kg) / [Height (m)]²
Prime Formula: BMI Prime = BMI / 25.0
BODY MASS INDEX
22.9
You are in the Normal Weight range.
World Health Organization (WHO) BMI Categories
| Category | BMI Range (kg/m²) | BMI Prime | Health Risk |
|---|---|---|---|
| Severe Thinness | < 16.0 | < 0.64 | Very High |
| Moderate Thinness | 16.0 – 16.9 | 0.64 – 0.68 | Moderate |
| Mild Thinness | 17.0 – 18.4 | 0.68 – 0.74 | Mild |
| Normal Weight | 18.5 – 24.9 | 0.74 – 1.00 | Lowest Risk |
| Overweight (Pre-obese) | 25.0 – 29.9 | 1.00 – 1.20 | Increased |
| Obese Class I | 30.0 – 34.9 | 1.20 – 1.40 | High |
| Obese Class II | 35.0 – 39.9 | 1.40 – 1.60 | Very High |
| Obese Class III (Severe) | ≥ 40.0 | > 1.60 | Extremely High |
BMI Frequently Asked Questions
What is Body Mass Index (BMI)?
Body Mass Index (BMI) is a clinical screening metric that estimates body fatness based on the ratio of a person's weight to their height squared (kg/m²). It is widely used by the World Health Organization (WHO) to classify individuals into underweight, normal weight, overweight, and obesity categories.
What is considered a normal or healthy BMI?
For adults aged 20 and older, a normal and healthy BMI is defined by the WHO as between 18.5 and 24.9. A BMI below 18.5 is considered underweight, 25.0 to 29.9 is overweight, and 30.0 or higher is categorized as obesity.
What are the limitations of the BMI calculator?
BMI does not directly measure body fat percentage or muscle mass. Athletes and bodybuilders with high lean muscle mass may have a high BMI despite having very low body fat. Conversely, older adults who have lost muscle mass may have a normal BMI despite having excess visceral fat.
What is BMI Prime?
BMI Prime is the ratio of your actual BMI to the upper limit of normal BMI (25.0). A BMI Prime of 1.0 means you are at the exact upper boundary of normal weight. Values under 0.74 suggest underweight, 0.74–1.00 is optimal, and over 1.00 indicates overweight.
