Body Mass Index (BMI) is a person's weight in kilograms divided by the square of height in meters. BMI is an inexpensive and easy screening method for weight category—underweight, healthy weight, overweight, and obesity.
The BMI calculation formula is:
BMI = weight (kg) / height² (m²)
For imperial units: BMI = (weight in pounds / height in inches²) × 703
Is BMI accurate for everyone?
BMI is a screening tool, not a diagnostic tool. It doesn't account for muscle mass, bone density, or body composition. Athletes and very muscular people may have a high BMI but not have excess body fat.
What's a healthy BMI range?
For most adults, a BMI between 18.5 and 24.9 is considered healthy. However, the ideal range can vary based on factors like age, sex, and ethnicity.
Should children use the same BMI categories?
No, BMI categories for children and teens are different from adults and are based on age and sex-specific percentiles.