Statistics and Indicators

Body Mass Index categories - adults


    BMI categories, 18 years and over, ACT General Health Survey, 2011-2020


    Body Mass Index (BMI) is a simple index of weight-for-height that is commonly used to classify underweight, healthy weight, overweight and obesity. 

    BMI for adults aged 18 years and over are grouped as follows:

    Underweight: BMI less than 18.5
    Healthy weight: BMI 18.5 - 24.99
    Overweight: BMI 25.00 - 29.99
    Obese class 1: BMI 30.00 -  34.99
    Obese class 2: BMI 35.00 - 39.99
    Obese class 3: BMI 40 or more


    In 2020, 38.7% of respondents aged 18 years and over were in the healthy weight BMI category. Males aged 18 years and over were significantly more likely to report being overweight than females (42.0% vs 29.8%).

    For the purpose of reporting the ACT General Health Survey data on HealthStats, if the 95% confidence intervals of the estimates do not overlap, they are considered to be significantly different.  

    BMI is based on self-reported height and weight.

    Note: The indicator shows self-reported data collected through Computer Assisted Telephone Interviewing (CATI). Estimates were weighted to adjust for differences in the probability of selection among respondents and were benchmarked to the estimated residential population using the latest available Australian Bureau of Statistics population estimates.

    Persons includes male, female, other and refused sex respondents and may not always add to the sum of male and female.

    The following estimates have a relative standard error of 25% to 50% and should be used with caution:

    • 2011/12: underweight males, underweight females
    • 2013/14: underweight males, underweight females
    • 2015/16: underweight persons, underweight females
    • 2018: underweight persons, underweight females

    The following estimates have not been published due to small numbers:

    • 2015/16: underweight males, obese class 2 and class 3 males
    • 2018: underweight males, obese class 2 and class 3 males
    • 2020: underweight males, underweight females, obese class 2 and class 3 males, obese class 2 and class 3 females 

    Statistically significant differences are difficult to detect for smaller jurisdictions such as the Australian Capital Territory. Sometimes, even large apparent differences may not be statistically significant. This is particularly the case in breakdowns of small populations because the small sample size means that there is not enough power to identify even large differences as statistically significant.

    To access the data please click on the "View source data" link at the bottom of the visualisation. This link will open up a data table that you can download.