What is BMI (Body Mass Index)?
Also written as：Body Mass Index ／ Body Mass Index (BMI)
BMI is a body size index calculated by dividing body weight (kg) by the square of height (m). It is widely used in health checkups as a general guide to obesity and underweight. Because it does not directly reflect muscle mass or visceral fat, it is evaluated together with other measurements such as waist circumference.
Reference range guideline
Generally, 18.5–24.9 is considered normal, 25 or above is considered obese, and below 18.5 is considered underweight (as classified by the Japan Society for the Study of Obesity).
* Reference ranges vary by testing facility, measurement method, age, sex, and other factors. Please check the reference range printed on your result sheet.
How to interpret an out-of-range result
If BMI is high, it is assessed alongside waist circumference, blood glucose, blood pressure, and lipids as part of lifestyle disease risk evaluation. If BMI is too low, a review of nutritional status is also recommended.
Related tests and conditions
Related terms
Sources & references
This page provides general information only and is not intended for diagnosis or treatment. Please consult the physician at your chosen facility regarding the interpretation of your health checkup results.