Waist-to-Height Ratio (WHtR) Calculator

Measure waist and height in the same units — the ratio is identical in cm or inches.

The rule. Keep your waist to less than half your height (ratio < 0.5). Bands: < 0.4 possibly underweight, 0.4–0.49 healthy, 0.5–0.59 increased risk, ≥ 0.6 high risk. The same boundary applies to men and women.

How do you calculate waist-to-height ratio?

Divide the waist circumference by height: WHtR = waist ÷ height. Because it is a ratio, the units cancel — a waist of 80 cm with a height of 170 cm gives 0.47, the same value you would get in inches. Measure the waist at its narrowest point, roughly at the navel.

What is a healthy waist-to-height ratio?

The simple guideline is to keep your waist under half your height, i.e. a ratio below 0.5. Values of 0.4–0.49 are considered healthy, 0.5–0.59 indicate increased central fat and risk, and 0.6 or above indicate high risk. A ratio under 0.4 can suggest you are very lean or underweight.

Why use waist-to-height ratio instead of BMI?

WHtR measures central (abdominal) fat, which is more strongly tied to heart disease and type 2 diabetes than overall weight. Unlike BMI it needs no sex- or age-specific charts, and the “half your height” rule is easy to remember. Several studies find it predicts cardiometabolic risk at least as well as BMI or waist circumference alone.

Does the 0.5 boundary apply to children?

The “keep your waist to less than half your height” message has been proposed for children and adults alike, which is one of its attractions. Growth charts and clinical judgement still matter for children, so use this as a screening rule rather than a diagnosis. Part of the appeal is that the ratio needs no age- or sex-specific chart, which is what makes a single boundary plausible across a wide age range at all. Whoever you are measuring, take the waist at the same landmark — between the lowest rib and the top of the hip bone — because the 0.5 boundary only holds if the measurement is taken consistently.

How should I measure my waist?

Stand relaxed and breathe out normally, then measure at the narrowest point between the lowest rib and the top of the hip bone — around the navel for most people. Keep the tape horizontal and snug without compressing the skin, and measure height without shoes. Use the same units for both.