Home
Back
BMI Formula:
| From: | To: |
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 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: The formula 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 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, height in meters, and age in years. All values must be valid (weight > 0, height > 0, age ≥ 18).
Q1: What are the BMI categories for adults?
A: Underweight (<18.5), Normal weight (18.5-24.9), Overweight (25-29.9), Obese (≥30).
Q2: How accurate is BMI?
A: BMI is a useful screening tool but is not diagnostic of body fatness or health. Athletes may have high BMI due to muscle mass, while older adults may have normal BMI but reduced muscle mass.
Q3: Why is age included in this calculator?
A: While BMI calculation doesn't use age, the percentile estimation (when implemented) would use age and gender-specific population data.
Q4: What are the limitations of BMI?
A: BMI doesn't distinguish between muscle and fat mass, doesn't account for fat distribution, and may not be accurate for certain populations like athletes, pregnant women, or the elderly.
Q5: Should BMI be used alone to assess health?
A: No, BMI should be used along with other assessments like waist circumference, diet, physical activity, and family history for a complete health evaluation.