Calculate your Body Mass Index (BMI) with metric or imperial measurements. Includes health risk classification and ideal weight range — free.
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Enter your height and weight. The BMI formula is: weight (kg) / height² (meters). In imperial: 703 × weight (lbs) / height² (inches). A BMI of 18.5-24.9 is considered healthy.
Underweight: below 18.5. Normal weight: 18.5–24.9. Overweight: 25–29.9. Obese: 30 and above. These are WHO guidelines for adults. BMI ranges for children differ by age and sex.
BMI is a useful screening tool but has limitations. It doesn't distinguish between muscle and fat, so muscular athletes may show as 'overweight' even at low body fat. It's also less accurate for elderly people who lose muscle mass. Use BMI as a guide, not a diagnosis.
For a healthy BMI of 18.5-24.9, your ideal weight range varies by height. Example: at 5'8" (173cm), the healthy weight range is approximately 125-163 lbs (57-74 kg). The calculator shows your specific range based on your height.
BMR is the number of calories your body burns at complete rest to maintain basic functions (breathing, circulation, organ function). It's the minimum calories needed per day. Multiply by an activity factor to find your daily calorie needs.