What is BMI?

The BMI or Body Mass Index is a simple measurement calculated by dividing your weight by your height squared. It is a quick and easy measure of your health and risk of chronic disease. BMI determines whether someone is underweight, overweight, obese or at a healthy weight in relation to their height. As weight increases or decreases out of the healthy weight range, it can increase the risk of health problems.

Check your body mass index now with our easy to use calculator. Remember to enter your height in centimetres and your weight in kilograms.

While it is less accurate for people under 18, pregnant women and highly trained athletes (who often have a high body mass index because of muscularity rather than body fat), it is a reliable measure of your overall health. While it is purely an indicator, it is an excellent starting point for a discussion around dietary interventions with an Accredited Practising Dietitian.

What do the results mean?

Underweight BMI


BMI: < 18.5

Healthy Weight BMI


BMI: 18.5 – 25.0

OverWeight BMI


BMI: 25.0 – 30.0

Obese BMI


BMI: > 30

The results show your BMI category and the normal weight range for a body mass index of 18.5 to 25. If your BMI is above 25 you should generally consider losing some weight while if the BMI is below 18.5, you need to consider gaining some weight. These results should be discussed with your dietitian or medical practitioner before taking much action as body mass index should be considered with a range of other factors.

There is an increased risk for a number of health conditions related to being overweight and obese. These include Type 2 diabetes, stroke, coronary heart disease, respiratory issues, cancer, arthritis, hypertension and sleep apnea. Three other strong indicators of such issues are waist circumference, high blood pressure and lack of physical activity. If you have any concerns, these should be discussed further with a Healthier You dietitian.

The risk of a number of these diseases can be significantly reduced by maintaining a healthy weight, eating a well-balanced diet and exercising regularly.

Studies show that even small amounts of weight loss notably lower your risk of Type 2 diabetes, heart disease and stroke.