BMI Calculator

BMI (Body Mass Index) is a measure of body fat based on height and weight. It's calculated using the formula: BMI = weight (kg) / height (m)². For imperial units: BMI = (weight in pounds × 703) / (height in inches)². BMI provides a general indication of whether you're underweight, normal weight, overweight, or obese.

BMI categories are: Underweight (<18.5), Normal weight (18.5-24.9), Overweight (25-29.9), and Obese (≥30). These categories are based on population studies and provide general health risk indicators. However, BMI doesn't account for muscle mass, bone density, or body composition.

BMI is a useful screening tool but has limitations. It may not be accurate for athletes with high muscle mass, older adults with low muscle mass, pregnant women, or people with certain medical conditions. It's best used as a starting point for health discussions with healthcare providers.

Our calculator supports both metric (kg, cm) and imperial (lbs, ft/in) units. The calculation method is the same, but the formulas differ slightly. Metric uses weight in kilograms divided by height in meters squared, while imperial uses weight in pounds times 703 divided by height in inches squared.

BMI can be checked monthly or quarterly for adults. For children and teens, BMI should be calculated using age and sex-specific percentiles. Remember that BMI is just one health indicator - focus on overall health, fitness, and lifestyle habits rather than BMI alone.

If your BMI is outside the normal range, consult with a healthcare provider. They can assess your overall health, consider other factors like body composition, and provide personalized recommendations for achieving and maintaining a healthy weight.

BMI calculations are the same for men and women, but the health implications may differ. Women typically have higher body fat percentages than men at the same BMI. Age, ethnicity, and individual body composition also affect BMI interpretation.

Higher BMI is associated with increased risk of heart disease, diabetes, high blood pressure, and certain cancers. Very low BMI may indicate malnutrition or other health issues. However, BMI is just one risk factor - overall lifestyle, genetics, and other health indicators are equally important.