Body Mass Index

.Select  "Computer BMI" and your BMI will appear below .

BMI is intended for adults only, as children and adolescents are constantly growing. This makes it difficult to have set values for BMI cut-offs for young people. However, in adults who have stopped growing, an increase in BMI is usually caused by an increase in body fat.

You can use the body mass index (BMI) calculator for adults to calculate your BMI, provided you know your:

• weight in kilograms (kg)

• height in centimetres (cm).

Your BMI will classify you as ‘underweight’, ‘healthy weight’, ‘overweight’ or ‘obese’, as defined by the World Health Organization. If your BMI is:

• under 18.5kg/m2 – you are considered underweight and possibly malnourished

• 18.5 to 24.9kg/m2 – you are within a healthy weight range for young and middle-aged adults

• 25.0 to 29.9kg/m2 – you are considered overweight

• over 30kg/m2 – you are considered obese.

For older Australians over the age of 70 years, general health status may be more important than being mildly overweight. Some researchers have suggested that a BMI range of 22–26 kg/m2 is desirable for older Australians.

BMI isn’t always the best measure of health

At the population level, BMI is used to indicate level of risk for morbidity (disease risk) and mortality (death rates).

Differences in BMI between individual adults of the same age and sex are usually due to body fat, however there are many exceptions to this rule, which is why a BMI figure may not always be accurate.

BMI calculations will overestimate the amount of body fat for:

• body builders

• some high-performance athletes

• pregnant women.

BMI calculations will underestimate the amount of body fat for:

• the elderly

• people with a physical disability, who are unable to walk and may have muscle wasting.

BMI is also not an accurate indicator for people with: