About this tool
BMI is your weight in kilograms divided by your height in metres squared. For adults, healthdirect gives these ranges: under 18.5 is underweight, 18.5 to 24.9 is the healthy weight range, 25.0 to 29.9 is overweight, and 30.0 or above is obese.
BMI is quick, but it is less accurate for some people, including athletes and body builders, pregnant women, people with a physical disability, people under 18, and some population groups. That is why your waist measurement and your GP's view matter too.
Source: healthdirect Australia, Body mass index (BMI) and waist circumference, read on 13 October 2026.