Waist-to-Height Ratio Calculator

What this calculator does & how it works

The waist-to-height ratio is one of the simplest health screens there is: WHtR = waist circumference / height, both measured in the same unit. This calculator does the division for you and converts between metric and imperial so the result is identical either way. Because both measurements use the same unit, the ratio is dimensionless — a number like 0.48 or 0.55.

The appeal of WHtR is the memorable rule behind it: keep your waist to less than half your height. That single boundary (a ratio of 0.5) has held up reasonably well across many populations as a flag for raised cardiometabolic risk, which is why bodies such as the UK's National Institute for Health and Care Excellence (NICE) have discussed it as a practical complement to BMI.

How to interpret your results

A common reading of the bands is: below 0.5 — generally healthy; 0.5 to 0.6 — increased risk; 0.6 and above — high risk. Very low ratios (well under 0.4) may warrant a conversation too. These are screening boundaries, not diagnoses — they describe statistical patterns across groups, not certainty about any individual.

WHtR shines because it captures where you carry weight. Abdominal (visceral) fat is more metabolically active and more strongly tied to risk than fat on the hips or limbs, and that is exactly what your waist measurement reflects. Reading WHtR alongside your BMI gives a fuller picture than either number alone.

Measuring your waist correctly

Accuracy depends entirely on a good waist measurement. Stand relaxed and measure around your bare abdomen at the midpoint between the bottom of your lowest rib and the top of your hip bone — for most people this is roughly level with the belly button. Breathe out normally, and keep the tape snug against the skin without compressing it. Don't measure over clothing or pull the tape tight, both of which distort the result.

Limitations and when to consult a professional

WHtR is a fast screen, not a verdict. The 0.5 boundary is a generalization; appropriate cut-offs can differ by age, sex, ethnicity, and during pregnancy, and the ratio tells you nothing about fitness, diet quality, blood pressure, or blood sugar. A single measurement can also be thrown off by a large meal, bloating, or tape placement. If your ratio is elevated, or you have other risk factors such as family history, high blood pressure, or high cholesterol, talk to a doctor who can order the right tests and interpret them in context. Nothing here is medical advice.

Frequently asked questions