BMI Calculator

Calculate your Body Mass Index using metric or imperial units.

Select units, enter weight and height, then calculate.

BMI Categories (WHO Standard for Adults):

  • Underweight: < 18.5
  • Healthy weight: 18.5 – 24.9
  • Overweight: 25 – 29.9
  • Obesity Class I: 30 – 34.9
  • Obesity Class II: 35 – 39.9
  • Obesity Class III: ≥ 40

Note: BMI is a screening tool and doesn't directly measure body fat. Muscle mass can influence results. Consult a healthcare professional for personalized health assessment.

Understanding Your Body Mass Index (BMI)

Body Mass Index (BMI) is a widely used screening tool to categorize weight status relative to height. It provides a simple, inexpensive way to identify potential weight problems for adults. While not a direct measure of body fat, BMI correlates moderately well with more direct measures and is often used in population studies and initial health assessments.

How to Use the BMI Calculator

  1. Select Units: Choose either "Metric" (kilograms and centimeters) or "Imperial" (pounds, feet, and inches). The input fields will adjust accordingly.
  2. Enter Weight: Input your current weight in the selected unit (kg or lbs).
  3. Enter Height:
    • For Metric: Enter height in centimeters (cm).
    • For Imperial: Enter height in feet (ft) and inches (in).
  4. Click Calculate: Press the button to compute your BMI.

The calculator will display your calculated BMI value and indicate the corresponding weight category based on the World Health Organization (WHO) standard classifications for adults.

BMI Formulas

  • Metric: BMI = Weight (kg) / [Height (m)]² *(Note: Calculator uses cm input and converts)*
  • Imperial: BMI = [Weight (lbs) / [Height (in)]²] x 703

Interpreting Your BMI Result

The calculated BMI falls into one of several categories:

  • Underweight (Below 18.5): May indicate malnutrition or other health issues.
  • Healthy Weight (18.5 - 24.9): Generally considered the range with the lowest risk of weight-related health problems.
  • Overweight (25.0 - 29.9): Associated with an increased risk of developing certain health conditions.
  • Obesity (30.0 and above): Subdivided into classes (I, II, III), associated with a significantly higher risk of chronic diseases like heart disease, type 2 diabetes, and certain cancers.

Limitations of BMI

It's crucial to understand that BMI is a screening tool, not a diagnostic one. It has limitations:

  • Doesn't Distinguish Fat from Muscle: Muscular individuals (like athletes) may have a high BMI but low body fat, placing them incorrectly in overweight/obese categories.
  • Doesn't Account for Body Composition Changes: Older adults may lose muscle and gain fat but maintain the same BMI.
  • Distribution of Fat Not Considered: Fat stored around the abdomen poses higher health risks than fat elsewhere, which BMI doesn't measure.
  • Ethnic Variations: Optimal BMI ranges may differ slightly for different ethnic groups.
  • Not for Children/Teens: Different charts (BMI-for-age percentiles) are used for evaluating weight status in children and adolescents.

Conclusion

The BMI calculator is a useful starting point for assessing your weight status relative to population norms. However, it should be interpreted cautiously and ideally discussed with a healthcare professional who can consider your individual body composition, health history, lifestyle, and other relevant factors for a complete health assessment.