Waist-to-Height Ratio Calculator

Waist-to-height ratio (WHtR) compares the size of your waist to your height. It's a quick way to screen for central body fat — fat carried around the abdomen — which is more closely linked to metabolic and cardiovascular risk than overall weight is. Because it uses a ratio, the same simple threshold works across a wide range of body sizes.

The headline rule is easy to remember: keep your waist to less than half your height — a ratio under 0.50. A ratio of 0.50–0.59 suggests increased risk and is a reasonable prompt to look at diet, activity, and other health markers; 0.60 and above suggests higher risk. A lower ratio generally reflects less central fat.

Like BMI, WHtR is a screen, not a diagnosis. A raised ratio is a signal to look closer — ideally alongside blood pressure, blood glucose, and a conversation with a clinician — not a conclusion on its own.

WHtR is most useful for adults screening for central-fat risk, and it works well as a companion to BMI: BMI captures weight-for-height, WHtR captures where the weight sits. Measured carefully and consistently, it's a strong, low-effort indicator.

It is less applicable to children and adolescents (who need age-specific references), during pregnancy, and for people whose waist shape is affected by factors other than fat. As with any tape-based measure, inconsistent placement or tension is the most common source of error, so measure the same way each time.

Formula. WHtR = waist circumference ÷ height, with both measurements taken in the same units (the calculator converts to centimetres first, so the result is a unitless ratio). Enter your waist and height in cm or inches — the ratio is identical either way.

Boundary values. We use the boundary-value bands popularised by Ashwell and colleagues: below 0.40 (lean), 0.40–0.49 (healthy), 0.50–0.59 (increased risk), and 0.60 or above (high risk). The practical public-health message distilled from this work is the "waist less than half your height" rule.

Confidence. We label WHtR high confidence: it is a simple, extensively studied indicator that is often at least as predictive of health risk as BMI. That reflects the strength of the evidence for the screen — not a claim that a single ratio diagnoses any condition.