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BMI Equation:
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Body Mass Index (BMI) is a simple index of weight-for-height that is commonly used to classify underweight, normal weight, 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 standard BMI formula:
Where:
Explanation: The formula calculates body mass per unit of height squared to estimate body fatness and health risks.
Details: BMI provides a simple numeric measure that helps identify potential weight problems in adults. While not a direct measure of body fat, it correlates with more direct measures of body fat and is a quick screening tool for weight categories that may lead to health problems.
Tips: Enter weight in kilograms and height in meters. For accuracy, measure weight without heavy clothing and height without shoes. All values must be valid (weight > 0, height > 0).
Q1: What are the standard BMI categories?
A: Underweight (BMI < 18.5), Normal weight (18.5-24.9), Overweight (25-29.9), Obese (≥30).
Q2: Is BMI the same for men and women?
A: The calculation is the same, but interpretation may vary slightly as women typically have higher body fat percentages than men at the same BMI.
Q3: What are the limitations of BMI?
A: BMI doesn't account for muscle mass, bone density, overall body composition, or racial/ethnic differences. Athletes may have high BMI due to muscle rather than fat.
Q4: How often should I check my BMI?
A: For most adults, checking every 6-12 months is sufficient unless actively trying to lose or gain weight.
Q5: Should children use this calculator?
A: No, children and teens need age- and sex-specific BMI percentiles rather than the adult categories.