BMI basics and limitations

Learn the basic BMI formula and why BMI should be treated as a screening measure.

What BMI is

Body mass index is calculated from weight and height. In metric units, BMI equals weight in kilograms divided by height in meters squared.

What BMI can and cannot tell you

BMI is a broad screening measure. It does not directly measure body fat, muscle mass, fat distribution or every factor that influences health. Two people with the same BMI can have different body compositions and health circumstances.

Use the result carefully

The BMI Calculator is useful for understanding the formula and obtaining a general estimate. It should not be used by itself to diagnose a condition or make a medical decision.