Free BMI Calculator
Calculate your Body Mass Index and find your healthy weight range. Supports both metric and imperial units.
BMI Categories
Note: BMI is a general indicator and does not account for muscle mass, bone density, or overall body composition.
How to Use the BMI Calculator
Select Your Unit System
Choose between metric (kg/cm) or imperial (lbs/inches) units. The calculator automatically converts between systems so you can use whichever you prefer.
Enter Your Weight
Input your current weight in kilograms or pounds. For the most accurate result, weigh yourself in the morning before eating, wearing minimal clothing.
Enter Your Height
Input your height in centimeters or feet and inches. Stand straight against a wall without shoes for the most accurate measurement.
View Your BMI Results
Click calculate to see your BMI score along with your weight category (underweight, normal, overweight, or obese). The tool also shows your healthy weight range.
Pro tip: Your data is processed entirely in your browser. Nothing is sent to any server, ensuring complete privacy.
Understanding BMI
Body Mass Index (BMI) is a measure of body fat based on height and weight. While not a perfect measure, it provides a useful starting point for understanding if you are at a healthy weight. BMI is calculated by dividing your weight in kilograms by the square of your height in meters.
BMI Categories
- Underweight: BMI below 18.5
- Normal weight: BMI 18.5 to 24.9
- Overweight: BMI 25 to 29.9
- Obese: BMI 30 or higher
Frequently Asked Questions
What is BMI and how is it calculated?
BMI (Body Mass Index) is a measure of body fat based on height and weight. It is calculated by dividing your weight in kilograms by the square of your height in meters (kg/m²). In imperial units, it is weight in pounds divided by height in inches squared, multiplied by 703.
What are the BMI categories?
BMI categories are: Underweight (below 18.5), Normal weight (18.5-24.9), Overweight (25-29.9), and Obese (30 and above). These ranges help identify potential health risks associated with body weight.
Is BMI accurate for everyone?
BMI is a useful screening tool but has limitations. It may overestimate body fat in athletes with high muscle mass and underestimate it in older adults who have lost muscle. It also does not account for fat distribution or other health factors.
What is a healthy BMI for adults?
A healthy BMI for adults is generally between 18.5 and 24.9. However, optimal BMI can vary based on age, sex, ethnicity, and individual health conditions. Consult a healthcare provider for personalized advice.
How often should I check my BMI?
For most adults, checking BMI once or twice a year is sufficient unless you are actively trying to change your weight. Regular monitoring can help track progress toward weight management goals.
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