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BMI Formula:
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Body Mass Index (BMI) is a simple calculation using a person's height and weight. The formula is BMI = kg/m² where kg is a person's weight in kilograms and m² is their height in meters squared. BMI provides a reliable indicator of body fatness for most people.
The calculator uses the standard BMI formula:
Where:
Explanation: BMI is calculated by dividing weight in kilograms by the square of height in meters.
Details: BMI is a simple, inexpensive 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, height in meters, and optionally age. All values must be valid (weight > 0, height > 0). For most adults, BMI provides a good estimate of weight-related health risks.
Q1: What are the BMI categories?
A: Underweight (BMI < 18.5), Normal weight (18.5-24.9), Overweight (25-29.9), and Obese (≥30).
Q2: Is BMI accurate for everyone?
A: BMI may overestimate body fat in athletes and others with muscular builds, and underestimate body fat in older persons and others who have lost muscle.
Q3: How does age affect BMI interpretation?
A: For children and teens, BMI is age- and sex-specific and referred to as BMI-for-age. For adults, BMI interpretation is the same regardless of age or sex.
Q4: Are there limitations to BMI?
A: BMI doesn't distinguish between excess fat, muscle, or bone mass, nor does it provide any indication of the distribution of fat among individuals.
Q5: Should BMI be used alone to assess health?
A: No, BMI should be used as a screening tool, not a diagnostic tool. Other assessments like waist circumference, diet, physical activity, and family history should be considered.