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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 calculates body mass index by dividing weight by the square of height, providing a standardized measurement for weight classification.
Details: BMI provides a useful population-level measure of overweight and obesity. It is the most widely used diagnostic tool to identify weight problems in adults, though it should be used as a screening tool rather than a diagnostic of body fatness or health.
Tips: Enter weight in kilograms and height in meters. All values must be valid (weight > 0, height > 0). For accurate results, measure weight and height using standardized methods.
Q1: What are the BMI categories according to Australian guidelines?
A: Underweight (<18.5), Normal weight (18.5-24.9), Overweight (25-29.9), Obesity (≥30).
Q2: Are there limitations to BMI?
A: Yes, BMI doesn't account for muscle mass, bone density, overall body composition, and racial and sex differences. Athletes may have a high BMI but not have excess body fat.
Q3: How often should I check my BMI?
A: For most adults, checking BMI annually is sufficient unless you're actively trying to change your weight. Significant weight changes warrant more frequent monitoring.
Q4: Is BMI different for children?
A: Yes, BMI interpretation for children and teens considers age and sex-specific percentiles rather than fixed categories used for adults.
Q5: Where can I get more information about healthy weight in Australia?
A: The Australian Government Department of Health and state health departments provide comprehensive resources on maintaining a healthy weight.