Body mass index, or BMI, is used to determine whether you are in a healthy weight range for your height. It is useful to consider BMI alongside waist circumference, as waist measurement helps to assess risk by measuring the amount of fat carried around your middle. BMI is a useful measurement for most people over 18 years old. But it is only an estimate and it doesn’t take into account age, ethnicity, gender and body composition. We recommend you also check your waist measurement and other risk factors. Speak to your doctor, an Accredited Practising Dietitian or a health practitioner about your weight. This calculator shouldn’t be used for pregnant women or children.
Being a healthy weight means not being under or overweight. A BMI of 20-25 is considered healthy for most adults. However, BMI can be an inaccurate measure of healthy weight for pregnant women, children, older people, athletes or very muscular people. It may also need to be adjusted for some ethnic groups, including people of Asian, Aboriginal or Torres Strait Islander descent. Being underweight may be associated with lack of some vitamins and minerals that can affect important body functions, such as your immune response to infection and fertility or it can lead to a multitude of health issues from heart disease to bone problems. Being overweight or obese can lead to a multitude of health issues from heart disease, bone and joint problems as well as increase your risk of some cancers, sleep apnoea and type 2 diabetes. Putting on weight and trying to lose weight can be hard. Don’t be disheartened or de-motivated if progress is slow. It’s important to decide on small, practical changes that you feel comfortable with and that you’ll be able to stick to. It's helpful to get support from family or friends when you’re trying to change your weight.