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BMI Formula:
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Body Mass Index (BMI) is a simple index of weight-for-height that is commonly used to classify underweight, overweight, and obesity in adults. It is defined as a person's weight in kilograms divided by the square of their height in meters (kg/m²).
The calculator uses the BMI formula:
Where:
Explanation: The formula converts height from centimeters to meters by dividing by 100, then squares this value to calculate the body surface area.
Details: BMI provides a simple numeric measure of a person's thickness or thinness, allowing health professionals to discuss weight problems more objectively with their patients. It is used to screen for weight categories that may lead to health problems.
Tips: Enter weight in kilograms and height in centimeters. All values must be valid (weight > 0, height > 0). For accurate results, measure weight and height without shoes and heavy clothing.
Q1: What are the standard BMI categories?
A: Underweight: BMI < 18.5; Normal weight: BMI 18.5-24.9; Overweight: BMI 25-29.9; Obesity: BMI ≥ 30.
Q2: Is BMI accurate for everyone?
A: BMI may not accurately reflect body fat percentage in athletes (who may have more muscle mass), the elderly (who may have lost muscle mass), or certain ethnic groups.
Q3: Should children use the same BMI categories?
A: No, BMI for children and teens is interpreted relative to age and sex-specific percentiles because their body composition varies as they age.
Q4: What are the limitations of BMI?
A: BMI doesn't distinguish between muscle and fat, doesn't account for fat distribution, and may not be accurate for very short or very tall individuals.
Q5: How often should I check my BMI?
A: For most adults, checking BMI every few months is sufficient unless you're actively trying to change your weight. Significant weight changes warrant more frequent monitoring.