Waist-to-Hip Ratio Calculator
Calculate your waist-to-hip ratio and see which WHO risk category it falls into — a measure of fat distribution that BMI cannot capture.
How to use this calculator
- 1Measure your waist at its narrowest point, at the end of a normal breath out, with the tape snug but not compressing the skin.
- 2Measure your hips at the widest point around the buttocks.
- 3Both measurements must use the same unit — the ratio itself is unitless.
How the calculation works
WHR = waist circumference ÷ hip circumference- Waist
- Circumference at the narrowest point, usually just above the navel
- Hip
- Circumference at the widest point around the buttocks
The ratio is unitless, so it does not matter whether both measurements are in centimetres or inches — only that they use the same unit.
The WHO defines abdominal obesity as a ratio above 0.90 in men and above 0.85 in women. The thresholds differ because typical fat distribution differs between sexes, not because the underlying risk mechanism does.
Worked example
A man with an 85 cm waist and 100 cm hips
- 1.Ratio: 85 ÷ 100 = 0.85.
- 2.The WHO threshold for men is 0.90, and 0.85 is below it.
- 3.On the banded scale this falls in the low-risk category for men (0.90 or below).
Result: 0.85 — low risk for a man
Why where fat sits matters
BMI treats all body mass identically, which is its main structural weakness. Waist-to-hip ratio addresses a specific part of that gap: it describes the *distribution* of fat rather than the amount. Fat stored around the abdomen — particularly visceral fat, which packs around the organs rather than under the skin — behaves differently from fat stored on the hips and thighs, being more metabolically active and more strongly associated with insulin resistance and cardiovascular risk.
This is the basis of the familiar "apple versus pear" shorthand. Two people of identical height, weight and BMI can have quite different ratios, and the difference carries real information that BMI alone cannot supply.
How to measure it properly
The ratio is only as good as the measurements, and small technique errors move it noticeably.
- Waist — at the narrowest point of the torso, usually just above the navel. Measure at the end of a normal exhalation — not sucked in, not pushed out.
- Hips — at the widest point around the buttocks, with feet together.
- Tape position — the tape should be horizontal all the way round and snug against the skin without compressing it. A tape that dips at the back is a common source of error.
- Consistency — measure at the same time of day, ideally in the morning before eating, since abdominal measurements vary through the day.
What the ratio does not tell you
Waist-to-hip ratio is a screening indicator, not a diagnosis, and it has real blind spots. It cannot distinguish visceral fat from subcutaneous fat, which is the distinction that actually drives the metabolic risk — only imaging can do that. Very muscular people can have narrow hips relative to their waist without carrying excess fat at all. And because it is a ratio, losing fat from the hips raises it, which can make a genuine improvement look like a worsening.
For that last reason many clinicians now prefer waist circumference alone, or waist-to-height ratio, both of which respond more straightforwardly to abdominal fat loss.
What this assumes, and where it stops
Assumptions
- Both measurements are taken with the same unit and with correct tape technique.
- WHO thresholds apply. Some health bodies recommend lower cut-offs for people of South Asian, Chinese and other East Asian descent, where cardiometabolic risk rises at a lower ratio.
Limitations
- Cannot distinguish visceral fat from subcutaneous fat, which is the distinction that carries most of the metabolic risk.
- As a ratio, it can move for reasons unrelated to abdominal fat — losing hip and thigh mass raises it even if the waist is unchanged.
- Not validated for children, or during pregnancy.
- A screening indicator only. It is not a diagnosis and does not replace clinical assessment.
Common questions
Is waist-to-hip ratio better than BMI?
Neither replaces the other — they measure different things. BMI describes total mass relative to height; waist-to-hip describes where that mass sits. Used together they are more informative than either alone, which is why many clinical assessments record both plus waist circumference on its own.
Why are the thresholds different for men and women?
Because typical fat distribution differs. Women generally carry proportionally more fat on the hips and thighs, so the same ratio represents a different amount of abdominal fat than it would in a man. The WHO sets 0.90 for men and 0.85 for women to reflect that, not because the underlying risk mechanism differs.
Formula and content last reviewed on .
Results are estimates for information only, not professional advice.
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