Waist and hip circumference proportion
The number reports the relationship between the entered circumferences. No sex-specific or population-specific category is applied. A change in ratio can come from a change in waist, hips, or both, so keep the original measurements alongside it.
For a different circumference-based body-fat estimate, the Body Fat Calculator uses its own measurement method and assumptions.
The formula
The common measurement unit cancels in division. The ratio compares two circumferences rather than comparing waist with stature or body mass. Centimeter and inch calculations agree when both measurements are converted consistently.
Worked example
A waist circumference of 80 cm and hip circumference of 100 cm give a waist-to-hip ratio of 0.8, or 80%. The same proportions, such as 32 in and 40 in, give the identical ratio.
How to use this calculator
- Measure waist and hip circumferences with a consistent tape-measure protocol.
- Use the same unit for both fields and select that unit.
- Calculate the ratio and keep the original circumferences for comparison.
Measure anatomical sites consistently
Waist and hip measurements require a repeatable protocol. The WHO consultation discusses measurement methods and differences in interpretation across populations. Measure the waist using the chosen waist protocol and the hips around the broadest buttock circumference, with the tape horizontal. Avoid compressing the skin and repeat a measurement that appears inconsistent before recording a trend.
A ratio can hide different changes
A smaller waist-to-hip ratio does not by itself show which circumference changed. If both waist and hips shrink proportionally, the ratio may remain constant despite a body-size change. Clothing fit, body shape, and health assessment can require the separate measurements. This tool does not estimate body-fat percentage or infer a diagnosis from the ratio.
Assumptions & limitations
What this calculation assumes
- Both circumferences are measured using matching units and consistent anatomical sites.
What to keep in mind
- Excludes clinical risk classification, population cutoffs, and body-fat estimation.
Common questions
Can the ratio exceed one?
Yes. It exceeds one when the entered waist circumference is greater than the entered hip circumference.
Is this the same as waist-to-height ratio?
No. This denominator is hip circumference. Waist-to-height ratio uses stature and describes a different measurement relationship.
Can the ratio stay unchanged while measurements change?
Yes. Proportional changes in both circumferences keep the ratio the same, so retain the separate measurements.
Sources & further reading
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