Waist-to-Height Ratio Calculator

Waist-to-height ratio divides your waist circumference by your height. It sounds almost too simple to be useful, but a large and consistent body of research has found that it predicts cardiovascular and metabolic risk at least as well as BMI, and often better, because it directly measures the abdominal fat that BMI misses.

The rule of thumb is easy to remember: keep your waist to less than half your height. That single sentence works for children and adults, for men and women, and for people of different ethnic backgrounds, because height is doing the job of scaling. A waist of 85 cm on a 170 cm person gives a ratio of 0.500, right on the line. The same 85 cm waist on a 190 cm person is 0.447 and comfortably healthy.

Broadly, ratios under 0.4 suggest you may be underweight, 0.4 to 0.5 is considered healthy, 0.5 to 0.6 indicates increased risk, and above 0.6 signals high risk. Unlike the waist-to-hip ratio, this one does move when you lose abdominal fat, because the denominator — your height — never changes. That makes it a genuinely useful trend line: measure at the same point every few weeks and watch the number fall as your waist shrinks.

The measurement matters more than the maths. Stand relaxed, breathe out normally, and run the tape around the narrowest part of your torso, level with the floor. Do not suck in and do not pull the tape tight. Take the reading midway between your lowest rib and the top of your hip bone. Because the ratio is such a blunt, forgiving tool, being consistent about where you measure is far more important than measuring with millimetre precision.

This calculator returns estimates for general information only. It is not medical advice, diagnosis or treatment, and it cannot replace an assessment by a qualified health professional. Individual results vary, and figures such as calorie needs, body-fat percentage and heart-rate zones are approximations based on population averages rather than measurements of you.