Australian BMI Calculator
Enter your height and weight to calculate your body mass index and compare it with the standard adult BMI categories used in Australia.
BMI is a screening measure, not a diagnosis. It does not directly measure body fat or account for every factor affecting health.
Calculate your BMI
Your result
How BMI Is Calculated
BMI compares weight with height using the formula weight (kg) ÷ height² (m²). For example, 70 kg at 1.70 m gives a BMI of about 24.2.
Adult BMI Categories
| Category | BMI range |
|---|---|
| Underweight | Below 18.5 |
| Healthy weight | 18.5–24.9 |
| Overweight | 25.0–29.9 |
| Obesity class I | 30.0–34.9 |
| Obesity class II | 35.0–39.9 |
| Obesity class III | 40.0 and above |
When BMI May Not Be Suitable
Adult BMI categories should not be used to assess children or pregnancy. BMI may also misrepresent risk for athletes and others with high muscle mass, and clinicians may interpret thresholds differently for some cultural backgrounds or health conditions.
Waist circumference, blood pressure, blood tests, family history, medicines and overall wellbeing can add important context.
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Frequently Asked Questions (FAQs)
The standard healthy-weight range for adults is a BMI from 18.5 to 24.9. Your individual health cannot be determined from BMI alone.
No. BMI can be less useful for children, during pregnancy, for older adults, and for people with high muscle mass. Ethnicity and body composition can also affect how risk is interpreted.
Metric BMI is weight in kilograms divided by height in metres squared. For imperial measurements, it is weight in pounds multiplied by 703, divided by height in inches squared.
Consider speaking with a GP if you are concerned about your weight, have had an unexplained weight change, or have other health risk factors. A clinician can interpret BMI alongside waist circumference, medical history and other measurements.
This tool provides general information only and does not replace medical, legal or workplace advice. If symptoms are severe or life-threatening, call 000.
