BMI Calculator
Calculate your Body Mass Index (BMI) to assess if you're at a healthy weight. Free, accurate, and easy to use BMI calculator.
Understanding BMI: Theory, Usage, and History
What is BMI?
Body Mass Index (BMI) is a simple calculation that uses your height and weight to determine if you're at a healthy weight for your height. It's calculated by dividing your weight in kilograms by your height in meters squared (kg/m²).
BMI Formula: Weight (kg) ÷ [Height (m)]²
BMI Categories
| BMI Range | Category | Health Risk |
|---|---|---|
| Below 18.5 | Underweight | Increased risk |
| 18.5 - 24.9 | Normal weight | Lowest risk |
| 25.0 - 29.9 | Overweight | Increased risk |
| 30.0 and above | Obese | High risk |
How to Use This Calculator
- Enter your height in centimeters or feet/inches
- Enter your weight in kilograms or pounds
- Click "Calculate BMI" to get your result
- Review your BMI category and health recommendations
Important: BMI is a screening tool and not a diagnostic tool. Consult with a healthcare professional for personalized health advice.
History of BMI
The Body Mass Index was developed by Belgian mathematician Adolphe Quetelet in the 1830s. Originally called the "Quetelet Index," it was designed to classify the average man for social physics studies.
The term "Body Mass Index" was coined by physiologist Ancel Keys in 1972. Keys conducted a study comparing different methods of measuring obesity and found that BMI was the best proxy for body fat percentage.
Today, BMI is widely used by healthcare professionals, researchers, and public health organizations worldwide as a simple screening tool for weight categories that may lead to health problems.
Limitations of BMI
- Does not distinguish between muscle and fat mass
- May not be accurate for athletes with high muscle mass
- Does not account for bone density differences
- May not be appropriate for all ethnic groups
- Does not consider fat distribution in the body
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Quick Tips
- • Measure yourself at the same time of day for consistency
- • BMI is most accurate for adults aged 18-65
- • Consider waist circumference as an additional measure
- • Consult a healthcare provider for personalized advice