Waist-to-Hip Ratio Explained: The Thresholds, and Where to Put the Tape

Where the tape goes, precisely

Stand up, feet close together, arms relaxed at your sides, and breathe out normally. For the waist, find the lowest rib you can feel and the top edge of the hip bone, and put the tape at the midpoint between them — for most adults that sits above the navel, not on it. The tape should be horizontal all the way round and snug enough not to slide, but never tight enough to press into the skin. Read the number at the end of the breath out, without pulling your stomach in.

For the hips, the rule is simpler: the widest circumference around the buttocks, wherever that happens to fall on you, with the tape horizontal and no clothing bunched underneath. Do both measurements twice and take the average, because a centimetre of slack moves a ratio by roughly one hundredth. Take an adult whose hips measure 39.5 inches: a waist of 35.5 inches gives 0.90, and the same person measured carelessly at the navel at 38 inches gives 0.96. Same body, different side of the WHO line.

What the ratio is actually measuring

It is a crude proxy for where your body stores fat rather than how much of it there is. Fat carried around the abdomen, particularly the visceral fat packed around the organs, tracks more closely with blood pressure, blood lipids and type 2 diabetes than fat carried on the hips and thighs. That is the whole reason the ratio exists: two people of identical weight and height can have very different metabolic profiles depending on distribution, and BMI cannot see the difference.

The weakness of a ratio is that it can move for the wrong reason. A number rises just as readily because the hips are narrow as because the waist is wide, so a slim person with a narrow pelvis can land above the cut-off with very little abdominal fat. This is why the WHO report publishes waist-only thresholds alongside the ratio, and why the two should be read together. The WHO also notes that its cut-offs were derived largely from European populations, and that lower waist values may be more appropriate for people of South Asian and some East Asian backgrounds.

What the number can and cannot decide

It is a screening measure, not a diagnosis. Crossing 0.85 or 0.90 does not mean you have a disease; it means abdominal fat is one of the things worth discussing at your next appointment, alongside blood pressure, a lipid panel and a blood glucose reading — which are the measurements that actually change management. Nobody is treated on the strength of a tape measure.

There are also situations where the ratio simply does not apply. It is not valid during pregnancy, it has no established cut-offs for children and adolescents, and it can read high in people who carry a lot of muscle rather than fat around the trunk. If you have had abdominal surgery, ascites, or a hernia, the waist measurement is measuring something other than fat. In all of those cases the number is noise, and the honest thing a calculator can do is say so.

Frequently asked questions

Which is more useful, waist-to-hip ratio or BMI?

Neither replaces the other, because they answer different questions: BMI describes overall size relative to height, the ratio describes where the weight sits. WHO recommends reading them together, with waist circumference as a third figure. Many clinicians now also use waist divided by height, where a value under 0.5 is the rule of thumb, precisely because it needs only one measurement and is harder to get wrong.

Should I breathe in or hold my stomach in while measuring?

Neither. The measurement is taken at the end of a normal breath out, with the abdomen relaxed. Holding your stomach in or measuring on a full inhale can shrink the waist by an inch or more, which is enough to move the ratio by two or three hundredths and put you on the other side of a cut-off. If you want the number to be useful over time, the only thing that matters is doing it the same way every time.

Can the ratio get worse while I am losing weight?

Yes, and it is not a sign that something is wrong. Fat is not lost evenly, so hips and thighs can shrink faster than the abdomen for a while, which raises the ratio even as both measurements fall. Watch the waist figure itself over the same period: if it is going down, the trend is in the right direction regardless of what the ratio does month to month.