What is Body Mass Index?

Body Mass Index (BMI) is a measure of body fat based on the height and weight that applies to both adult men and women.

BMI does not differentiate between body fat and muscle mass. So, body builders and people who have a lot of muscle bulk will have a high BMI but will not be classified as overweight or obese.

What are the BMI Classifications?

There are several BMI Classifications that are relevant to everyone. 

Classifications BMI
Underweight <19
Ideal BMI 19-25
Overweight 25-30
Obese >30
Severely Obese >35
Morbidly Obese >40
Super Obese >50

It is recommended that most people fit within the Ideal BMI category of 19 - 25 BMI. Lap-band Surgery is possible for anyone who falls within or over the Obese Classification, BMI of over 30.

Does it matter where the fat is distributed?

Fat is predominantly distributed around the waist for both males and females. It is also a risk factor for health complications such as cardiovascular disease and type II diabetes. Fat predominantly deposited around the hips and buttocks does not seem to carry this same risk level. 

How do you compare?

To find out your BMI calculation, enter your weight (kg) and height (m) in the BMI Calculator to the right.

Do you want to know more about obesity?

If you want to read more about obesity, please visit other pages on this site, specifically:

Or contact us for more information about any questions you have. 


  1. Victorian Government, Better Health Channel
  2. World Health Organisation, Global Database of Body Mass Index
© Dr Tony Patiniotis - Hobart Obesity Surgery Centre, Tasmania, Australia