Waist-to-hip ratio

How to measure your waist and hips

Waist: midway between the bottom of your ribs and the top of your hip bone, breathing out normally, tape snug but not compressing. Hips: the widest point around your buttocks, with your feet together — not at the hip bones, which is the usual mistake and the one that moves the ratio most.

Divide waist by hip. Both in the same unit — the arithmetic does not care which, but mixing them is the single most common bug in calculators for this, and it produces a confidently wrong answer rather than an error. If your result comes out above 1.0 for a man or above 0.95 for a woman, check you have not entered them the wrong way round.

What the WHO cut-offs mean

The World Health Organization treats a ratio of 0.90 or above in men, and 0.85 or above in women, as marking substantially increased risk of metabolic complications. These came from the 1999 definitions and were carried into the 2008 expert consultation report. Worth noting precisely: that 2008 consultation deliberately didnot set new cut-offs — choosing definitive cut-points was outside its scope. So these are widely used thresholds, not a recent verdict.

Your waist on its own matters more

This is the part most calculators omit entirely. Waist circumference by itself is generally the better single predictor of metabolic risk than the ratio is, because the ratio can be moved by either end of it. Gaining fat around the middle raises it. Losing muscle around the hips and glutes raises it too — which is why it can mislead in older adults, where both can be happening at once.

So this page shows your raw waist alongside the ratio, read against the thresholds for the population you select.

Waist cut-offs differ by ancestry

The WHO figures — 94 and 102 cm for men, 80 and 88 cm for women — were largely derived from European populations, and the WHO itself recommends that cut-off points be established by country or population group. For South Asian, Chinese and South-East Asian adults the International Diabetes Federation uses lower thresholds, around 90 cm for men and 80 cm for women. Japan is the striking exception and effectively inverts the sexes, at 85 cm for men and 90 cm for women.

There is no equivalent, well-established ancestry adjustment for the ratiocut-offs, only for absolute waist. Rather than invent one, this page leaves the ratio thresholds alone and adjusts only the waist bands.

The 0.7 ratio, and what it is not

A great deal of what is written about waist-to-hip ratio is about attractiveness rather than health, and 0.7 is the number usually quoted. That figure comes from research on body-shape preferences. It is a finding about what people in various studies said they found attractive — it is not a health threshold, not a target, and not something to aim a diet at. Treating a preference statistic as a clinical goal is how a measurement stops being useful.

For the measure UK guidance actually recommends alongside BMI, use thewaist-to-height ratio, whose bands are the same for everyone. Not valid in pregnancy or for children.