Waist-to-hip ratio calculator with WHO thresholds
Waist-to-hip ratio is waist circumference divided by hip circumference — a description of where body fat sits, which body mass index cannot see at all. This calculator does that division and shows the result against the World Health Organization thresholds of 0.90 for men and 0.85 for women. It reports which side of the line the number falls and nothing further: a threshold is a population-level marker, and turning one into a statement about an individual is a claim two tape measurements cannot support.
What people use it for
Adding the measure BMI leaves out
Two people with an identical body mass index can have quite different ratios, because BMI compares weight to height and cannot tell where any of it is. Measuring both takes two minutes and describes rather more than either does alone.
Tracking a direction over months
A single ratio says very little. The same tape, the same two places, the same time of day, every few months, says considerably more — and it does so without a scale, which some people find easier to live with.
Preparing for a conversation with a doctor
A measured number and the date it was taken is a better starting point than a description. If a result concerns you, that is precisely the thing to bring rather than to act on alone.
How it works
- Pick the sex and the unit — The WHO thresholds differ by sex. One unit control covers both fields, because the unit cancels in a ratio and mixing them is the only way to get a wrong answer.
- Measure the waist — At the narrowest point above the navel, standing upright, breathing out gently. Snug tape, not compressing.
- Measure the hips — At the widest part of the buttocks, with the tape level all the way round.
- Read the ratio and the threshold — The page shows the number to two decimal places and which side of the published cut-off it falls.
Questions
Why measure this as well as BMI?
They measure different things. BMI compares weight to height and cannot tell where any of it is; waist-to-hip ratio describes distribution and cannot tell how much there is. Two people at the same BMI can have very different ratios, which is the whole reason both exist.
I am just over the threshold. What does that mean?
Less than the sharpness of the line suggests. Thresholds are drawn for populations, not for people, and 0.86 is not meaningfully different from 0.84 for any individual. What is worth watching is the direction over months — and what it means for you specifically is a question for a doctor who can see the rest of the picture.
Does it matter whether I use centimetres or inches?
Not to the answer, as long as both measurements use the same one, because the unit cancels out in a ratio. It matters a great deal if you mix them, which is why there is a single unit control and why the tool refuses a waist more than half again the hip.
Why are the thresholds different for men and women?
Because the WHO publishes them separately, based on where risk starts to rise in each group. Body fat distribution differs enough between them that one number for everybody would be wrong for both.
Can I use this while pregnant?
No. The measure assumes the abdomen is not being displaced by anything, so during pregnancy the ratio does not mean what it normally means. Your antenatal team tracks what matters instead.
Tips
- Measure first thing, before eating, for the most repeatable reading.
- Breathe out gently — holding it in changes the waist measurement more than you would expect.
- Use the same tape every time. Cheap tapes stretch, and a stretched tape looks like progress.
- Both measurements in the same unit. The ratio does not care which one.
By Ahsan Mahmood · updated 2026-07-30
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