BMI Calculator
Calculate your Body Mass Index and discover your health category
< 18.5
18.5 - 24.9
25.0 - 29.9
30.0+
| Category | BMI Range | Health Risk |
|---|---|---|
| Underweight | Below 18.5 | Possible nutritional deficiency and osteoporosis |
| Normal Weight | 18.5 - 24.9 | Low risk of weight-related diseases |
| Overweight | 25.0 - 29.9 | Increased risk of health problems |
| Obese (Class I) | 30.0 - 34.9 | High risk of health problems |
| Obese (Class II) | 35.0 - 39.9 | Very high risk of health problems |
| Obese (Class III) | 40.0+ | Extremely high risk of health problems |
Medical Disclaimer
Important: This BMI calculator is for informational purposes only and should not be used as a medical diagnostic tool. BMI is not a direct measure of body fat and has limitations, especially for athletes, elderly individuals, and children. Please consult with a healthcare professional for personalized health advice and to discuss your weight and health goals.
What is BMI and How is it Calculated?
Body Mass Index (BMI) is a simple measure of body fat based on height and weight that applies to adult men and women. The BMI is calculated by dividing a person's weight in kilograms by the square of their height in meters. The formula is: BMI = weight (kg) ÷ height (m)².
For imperial measurements, the formula is: BMI = [weight (lbs) ÷ height (inches)²] × 703.
BMI Categories and What They Mean
The World Health Organization (WHO) and the CDC have established standard BMI categories. A BMI under 18.5 is considered underweight, which may indicate insufficient weight for your height and can be associated with nutritional deficiencies. A BMI between 18.5 and 24.9 is considered normal or healthy weight, representing the lowest risk category for weight-related health issues. A BMI between 25 and 29.9 is classified as overweight, indicating increased health risks. A BMI of 30 and above is considered obese, with further classifications for Class I (30-34.9), Class II (35-39.9), and Class III (40+) obesity.
Why Should You Know Your BMI?
Understanding your BMI can be a useful starting point for discussions with healthcare providers about your health. It can help identify potential health risks associated with weight, such as type 2 diabetes, heart disease, high blood pressure, and certain types of cancer. Maintaining a healthy BMI through balanced nutrition and regular physical activity is an important component of overall health and wellness.
Limitations of BMI
While BMI is a useful screening tool, it has important limitations. BMI doesn't distinguish between muscle and fat mass, so athletes with high muscle content may have a high BMI despite having low body fat. Age is also a factor—muscle naturally decreases with age while fat increases, so older adults may require different BMI interpretations. Ethnicity can play a role, as different populations may have different health risks at the same BMI. Additionally, BMI doesn't account for bone density, body composition, or overall fitness level. For these reasons, BMI should be used alongside other health assessments and professional medical advice.
Tips for Maintaining a Healthy BMI
Achieving and maintaining a healthy BMI involves a balanced approach to diet and exercise. Aim for at least 150 minutes of moderate-intensity aerobic activity or 75 minutes of vigorous-intensity activity per week. Eat a variety of nutrient-dense foods including fruits, vegetables, whole grains, lean proteins, and healthy fats. Limit sugary drinks, processed foods, and excessive salt intake. Get adequate sleep (7-9 hours per night) and manage stress through relaxation techniques. If you need help developing a personalized plan, consult with a registered dietitian or healthcare provider.