What is a healthy BMI?

For most adults, a BMI of 18.5–24.9 is considered healthy. BMI of 25–29.9 is overweight, and 30 or above is classified as obese. However, BMI has limitations and does not distinguish between muscle and fat.

Why is waist circumference important?

Waist circumference measures abdominal fat, which is a better predictor of chronic disease risk than BMI alone. For men, a waist over 94cm increases risk and over 102cm is high risk. For women, over 80cm increases risk and over 88cm is high risk.

BMI Calculator (Australia)

Units

Height (cm)

Weight (kg)

Sex (for waist circumference thresholds)

Male Female

Waist circumference (cm) — optional

Measure around your waist at the level of your belly button, halfway between your lowest rib and the top of your hip bone.

BMI is a useful population-level screening tool, but it has significant limitations for individuals:

It does not distinguish between muscle and fat — a muscular person may have a high BMI but low body fat. It doesn't account for body composition, bone density, age, or sex differences in fat distribution.

BMI thresholds were developed primarily from European populations. For people of some Asian backgrounds, health risks may increase at lower BMI levels (overweight ≥23, obese ≥27.5 — WHO Asian thresholds).

For Aboriginal and Torres Strait Islander people, waist circumference is considered a more clinically useful measure than BMI.

BMI should always be interpreted alongside waist circumference, clinical assessment, and other risk factors — not used in isolation.

Fat stored around the abdomen (visceral fat) is metabolically active and strongly linked to increased risk of type 2 diabetes, cardiovascular disease, and certain cancers — more so than fat on the hips or thighs.

Australian thresholds:

Men: > 94 cm = increased risk, > 102 cm = substantially increased risk

Women: > 80 cm = increased risk, > 88 cm = substantially increased risk

Measuring your waist circumference takes 10 seconds and tells you more about your health risk than BMI alone. Measure at belly button level, standing relaxed, after breathing out normally.