BMI Calculator
Calculate your Body Mass Index and understand what it means
Your BMI Result
Healthy BMI range: 18.5 kg/m² - 25 kg/m²
Healthy weight for your height: 52.2 kg - 70.3 kg
BMI Prime: 0.88
Ponderal Index: 13.4 kg/m³
How BMI is Calculated
The Basic Formula
Body Mass Index (BMI) is a simple index of weight-for-height that is commonly used to classify underweight, overweight, and obesity in adults. It is defined as the body mass divided by the square of the body height.
For those using imperial units (pounds and inches), the formula is slightly different:
Step-by-Step Calculation Process
Convert height to meters
Convert weight to kilograms
Square your height
Divide weight by height squared
BMI Categories
After calculating your BMI, you can determine which category you fall into:
| BMI Range | Category | Health Risk |
|---|---|---|
| Below 18.5 | Underweight | Possible nutritional deficiency, osteoporosis |
| 18.5 - 24.9 | Normal weight | Lowest risk of health problems |
| 25.0 - 29.9 | Overweight | Moderate risk of developing heart disease, diabetes |
| 30.0 - 34.9 | Obese (Class I) | High risk of developing heart disease, diabetes |
| 35.0 - 39.9 | Obese (Class II) | Very high risk of developing heart disease, diabetes |
| 40.0 and above | Extremely Obese (Class III) | Extremely high risk of life-threatening health problems |
Understanding BMI Prime
BMI Prime is a simple modification of the BMI system. It is the ratio of a person's BMI to the upper limit of the normal BMI range (25 kg/m²).
A BMI Prime less than 0.74 indicates underweight, between 0.74 and 1.00 indicates normal weight, and above 1.00 indicates overweight.
Limitations of BMI
While BMI is a useful screening tool, it does have limitations:
- It may overestimate body fat in athletes and others with a muscular build
- It may underestimate body fat in older persons and others who have lost muscle mass
- It doesn't account for distribution of fat (which is important for health risks)
- It may not be accurate for certain ethnic groups
Despite these limitations, BMI remains a widely used and valuable tool for assessing weight-related health risks in the general population.