BMI Calculator - Body Mass Index Calculator
Free online Body Mass Index (BMI) calculator. Calculate your BMI, weight status category, and healthy weight range for your height.
Inputs
🔒 Local ProcessingHow to Use This Calculator
- Select your preferred measurement units (Metric in kg/cm or Imperial in lbs/inches).
- Enter your current body weight accurately.
- Input your standing height without footwear.
- Review your calculated BMI score, World Health Organization category, and healthy weight targets.
Formula & Mathematical Method
Body Mass Index is defined as body mass divided by the square of body height. For imperial units, the formula is 703 × weight (lbs) / [height (in)]^2.
BMI = weight (kg) / [ height (m) ]^2Explanation of Variables
| Symbol | Variable Name | Description & Role in Calculation |
|---|---|---|
| W | Body Weight | Total measured body mass in kilograms (kg) or pounds (lbs). |
| H | Standing Height | Stature measured without shoes in centimeters (cm) or inches (in). |
| BMI | Body Mass Index | Ratio of mass in kilograms to the square of height in meters (kg/m²). |
Worked Calculation Examples
Healthy Adult
Scenario: Weight: 70kg, Height: 175cm (1.75m).
Athletic Individual
Scenario: Weight: 88kg, Height: 180cm (1.8m).
Interpretation of Results
Body Mass Index (BMI) is a clinical screening tool defined by the World Health Organization (WHO) that evaluates whether an adult is within a healthy weight range relative to their height. Standard ranges include Underweight (<18.5), Normal weight (18.5–24.9), Overweight (25.0–29.9), and Obese (≥30.0).
BMI Value (kg/m²)
Your calculated mass-to-height proportion categorized against standardized clinical thresholds.
Key Context: BMI is an epidemiological screening metric, not a definitive standalone diagnostic measurement.
Healthy Weight Range
The mass boundaries corresponding to a BMI between 18.5 and 24.9 for your specific height.
Key Context: Targeting this range is statistically associated with lower cardiovascular and metabolic health risks.
Practical Use Cases
Baseline Wellness Assessment
Determine whether your current body mass falls within standard statistical health ranges.
Weight Management Goal-Setting
Establish realistic target boundaries for long-term lifestyle and fitness adjustments.
Limitations & Key Assumptions
- BMI does not directly measure body fat percentage or distinguish between skeletal muscle mass and adipose tissue.
- Athletes and muscular individuals may register as overweight or obese despite possessing low body fat.
- Older adults with sarcopenia (muscle loss) may test as normal weight while harboring excess visceral fat.
- Results are statistical estimates and do NOT constitute medical diagnosis, clinical evaluation, or healthcare treatment plans.