BMI Calculator
Enter your weight and height to calculate your Body Mass Index (BMI) and determine your weight category instantly.
Calculator Overview
Inputs
- • Weight (kg): Your current body weight in kilograms.
- • Height (cm): Your current height in centimeters.
The Formula
The mathematical formula calculates your Body Mass Index by dividing your weight by the square of your height in meters:
BMI = Weight (kg) ÷ [Height (m)]²
Understanding Your BMI Results
Your BMI categorizes your weight status based on clinical guidelines established by the World Health Organization (WHO). Use the reference chart below to understand what your score means for your long-term health.
| Classification | BMI Range | Health Implications |
|---|---|---|
|
Underweight
|
Below 18.5 | Elevated risk of nutritional deficiency, weakened immune system, and osteoporosis. |
|
Healthy Weight
|
18.5 – 24.9 | Optimal range for lowest risk of weight-related illness and overall longevity. |
|
Overweight
|
25.0 – 29.9 | Moderate risk of heart disease, high blood pressure, and type 2 diabetes. |
|
Obesity
|
30.0 + | High risk of serious, chronic weight-related health conditions. |
Clinical Limitations of BMI
While BMI is an excellent rapid-screening tool, it is an imperfect measure of overall physiology. It relies solely on height and weight, meaning it cannot differentiate between lean muscle mass and fat mass, nor does it account for bone density or fat distribution.
Are you an athlete? A heavily muscled individual may register as "Obese" on the BMI scale while maintaining a very low, healthy body fat percentage. For a more accurate assessment of your body composition, use our Body Fat Calculator
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Frequently Asked Questions
What is BMI?
Body Mass Index (BMI) is a measure of body fat based on your weight and height. It is calculated as weight (kg) divided by the square of height (m²). BMI is used to categorize individuals into weight categories such as Underweight, Normal, Overweight, and Obese.
How is BMI calculated?
BMI is calculated using the formula: BMI = weight (kg) / (height (m)²). For example, if your weight is 70 kg and your height is 1.75 m, your BMI is 70 / (1.75 * 1.75) = 22.86, which falls in the Normal category.
What do the BMI categories mean?
BMI categories are: Underweight (below 18.5), Normal (18.5–24.9), Overweight (25–29.9), and Obese (30 and above). These categories help assess whether your weight is within a healthy range for your height.
What are the limitations of BMI?
BMI does not account for muscle mass, bone density, or overall body composition. For example, athletes with high muscle mass may have a high BMI but low body fat. It’s best used as a general guideline rather than a definitive measure of health.
How can I improve my BMI?
To improve your BMI, focus on a balanced diet and regular exercise. If your BMI is high, consider reducing calorie intake and increasing physical activity. If it’s low, focus on gaining healthy weight through nutrient-dense foods and strength training. Always consult a healthcare professional for personalized advice.