Source: Adapted from World Health Organization (WHO) 1995, WHO, 2000 and WHO 2004.
Exceptions to the rule
Muscles: BMI cannot distinguish between fat and muscle. Those with a higher than average muscle mass (body builders, athletes etc.) will end up with a misleadingly high BMI value.
Certain populations: BMI is also unsuitable for certain populations and individuals, including Aboriginal people, Torres Strait Islanders, Asian people, children, pregnant women and the elderly.
For all these reasons, you should treat it as a rough guide to be used in conjunction with other body-weight indicators.
Measuring your waist circumference is a great predictor of health risk for chronic diseases. No matter what your height or build, an increased waist line can be a sign that you are at increased risk for serious health problems.
The BMI calculation is a guideline only as it does not take into consideration fat to muscle ratio, which affects BMI results. Therefore, it may not be appropriate for athletes or those of muscular build.
The calculations on this site are estimates and content is provided for general information only. It should not be treated as a substitute for the medical advice of your own doctor or any other health care professional. Always consult your own GP if you're in any way concerned about your health.