BMI Calculator
| Underweight | < 18.5 |
| Healthy | 18.5–24.9 |
| Overweight | 25–29.9 |
| Obesity | 30.0 or above |
What Is a BMI Calculator?
The Body Mass Index (BMI) Calculator is a health assessment tool used to estimate a person's body fat based on height and weight. It offers a fast, general indication of whether someone is underweight, healthy, overweight, or obese. While it doesn’t directly measure fat percentage, BMI is widely used in clinical and personal health evaluations due to its simplicity and effectiveness.
How to Use the BMI Calculator
This calculator supports both standard (ft/in, lb) and metric (cm, kg) units. You can toggle between unit systems using the tab buttons. Input the required values in your preferred system, then click “Calculate” to see your BMI and category.
Standard Units — Select height using feet and inches dropdowns, then input weight in pounds. The tool automatically converts your input into inches and calculates BMI using the standard formula:
BMI = (Weight in pounds / Height in inches²) × 703.
Metric Units — Enter height in centimeters and weight in kilograms. The BMI is computed with the formula:
BMI = Weight in kg / (Height in meters)².
Result and Category — Once calculated, the result shows your BMI to two decimal places along with its classification. The categories used follow the global standard:
- Underweight – Less than 18.5
- Healthy – 18.5 to 24.9
- Overweight – 25.0 to 29.9
- Obesity – 30.0 and above
This tool can be used for personal health awareness, wellness programs, fitness goals, or initial screening by professionals. However, BMI may not be a complete indicator for athletes, children, or older adults due to differences in body composition.