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, normal weight, overweight and obesity in adults. It is calculated by dividing a person's weight in kilograms by the square of their height in meters.
The calculator uses the standard BMI formula:
Where:
Explanation: 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.
Details: BMI is an inexpensive and easy screening method for weight category—underweight, healthy weight, overweight, and obesity. While BMI doesn't measure body fat directly, research has shown that BMI is moderately correlated with more direct measures of body fat.
Tips: Enter weight in kilograms and height in meters. For accurate results, measure weight with minimal clothing and height without shoes. All values must be valid (weight > 0, height > 0).
Q1: What are the BMI categories for adults?
A: Underweight (BMI < 18.5), Normal weight (18.5-24.9), Overweight (25-29.9), Obesity (BMI ≥ 30).
Q2: Is BMI accurate for everyone?
A: BMI may overestimate body fat in athletes and others with muscular builds, and may underestimate body fat in older persons and others who have lost muscle.
Q3: How often should BMI be calculated?
A: For most adults, BMI should be checked at least annually as part of routine health screening.
Q4: Are there limitations to BMI?
A: BMI doesn't account for muscle mass, bone density, overall body composition, or racial and sex differences.
Q5: Should BMI be used alone for health assessment?
A: No, BMI should be used as a starting point for further assessment including waist circumference, diet history, exercise, and family history.