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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:
Interpretation: The result is compared against standard BMI categories:
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 serves as a screening tool for weight categories that may lead to health problems.
Tips: Enter weight in kilograms and height in meters. For height, you can convert from cm to m by dividing by 100 (e.g., 175 cm = 1.75 m). All values must be valid (weight > 0, height > 0).
Q1: Is BMI accurate for everyone?
A: BMI may overestimate body fat in athletes and those with muscular builds, and underestimate body fat in older persons who have lost muscle mass.
Q2: Does BMI differ by age or gender?
A: The same BMI categories apply to all adult men and women regardless of age, though health risks may differ at the same BMI for different populations.
Q3: What are the limitations of BMI?
A: BMI doesn't distinguish between muscle and fat, doesn't account for fat distribution, and may not be accurate for certain ethnic groups, pregnant women, or very muscular individuals.
Q4: Should children use this calculator?
A: No, children and teens need age- and sex-specific BMI percentiles rather than the adult categories.
Q5: What's a healthy BMI range?
A: For most adults, a BMI between 18.5 and 24.9 is considered healthy, though optimal BMI may vary by individual factors.