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BMI (Body Mass Index) 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 provides a simple numeric measure of a person's thickness or thinness, allowing health professionals to discuss weight problems objectively with their patients.
Details: BMI provides the most useful population-level measure of overweight and obesity as it is the same for both sexes and for all ages of adults. However, it should be considered a rough guide because it may not correspond to the same degree of fatness in different individuals.
Tips: Enter weight in kilograms and height in meters. For older adults (65+), BMI ranges may differ slightly from standard adult ranges due to changes in body composition with aging.
Q1: Are BMI ranges different for older adults?
A: Yes, for adults over 65, a BMI between 23-28 may be more optimal than the standard 18.5-25 range, as slightly higher BMI may be protective against osteoporosis and frailty.
Q2: What are the limitations of BMI?
A: BMI doesn't account for muscle mass, bone density, overall body composition, or racial and sex differences. Athletes may have high BMI due to muscle rather than fat.
Q3: How often should older adults check their BMI?
A: For seniors, monitoring weight changes is more important than BMI alone. Significant unintentional weight loss (>5% in 6-12 months) should be evaluated.
Q4: Should BMI be the only measure of healthy weight?
A: No, waist circumference and other measures of body composition should also be considered, especially in older adults where muscle loss (sarcopenia) may occur.
Q5: What's a healthy BMI for men over 65?
A: Many experts suggest a BMI between 23-27 for older men, as this range may be associated with lowest mortality risk in this age group.