In this article
Two people can weigh the same and have the same BMI, yet carry fat in different places. Fat stored around the middle is linked with higher health risk than fat stored on the hips and thighs. Waist-to-hip ratio (WHR) is a simple tape-measure check for that difference: waist circumference divided by hip circumference.
How to measure properly
- 1Stand relaxedFeet together, arms by your sides, breathe out normally. Do not pull your stomach in.
- 2WaistWrap the tape around the narrowest part of your torso, usually just above the belly button. If unclear, use the midpoint between the lowest rib and the top of the hip bone.
- 3HipMeasure around the widest part of your buttocks, with the tape level all the way round.
- 4Keep the tape snugFirm against the skin but not squeezing. Measure over light clothing or bare skin.
- 5DivideWaist ÷ hip, in the same unit (cm or inches). Repeat twice and average.
Measure at the same time of day, ideally in the morning before eating. Bloating after a meal can add a few centimetres.
A worked example
The unit cancels out, so centimetres and inches give the same ratio. Just do not mix them.
Where the lines are
The WHO report on waist circumference and waist-hip ratio (2008) describes abdominal obesity as a ratio of 0.90 or more in men and 0.85 or more in women. Other bodies use slightly different bands, and some risk tables are age-specific, so treat the lines as a guide.
The marker shows the 82 cm / 98 cm example. At or above 0.85, the WHO flags abdominal obesity.
The marker shows a man with a 96 cm waist and 102 cm hip: 96 ÷ 102 = 0.94, above the 0.90 line.
Same waist, different hips
WHR changes when either measurement changes. Take a waist of 85 cm. With narrower hips the ratio climbs, with wider hips it falls. That is why WHR describes shape, not just size.
With hip 100 cm the ratio is exactly 0.85. Wider hips lower the ratio, but only the waist side of the story is linked to the extra risk.
Different bodies, different results
| Waist (cm) | Hip (cm) | Ratio | Vs WHO lines |
|---|---|---|---|
| 70 | 96 | 0.73 | Under both lines |
| 78 | 100 | 0.78 | Under both lines |
| 82 | 98 | 0.84 | Just under 0.85 |
| 90 | 100 | 0.90 | At the men's line, over the women's |
| 96 | 102 | 0.94 | Over both lines |
| 100 | 104 | 0.96 | Over both lines |
The same ratio can sit on different sides of the line depending on sex. That is why the calculator asks which line to use.
WHR, waist-to-height and BMI compared
- Cannot tell fat from muscle
- Ignores where fat sits
- Easy to calculate
- Picks up belly fat
- Needs only a tape
- Not designed for children, pregnancy or athletes
None of them is perfect alone. Doctors often use several measures together.
Another simple rule is the waist-to-height ratio: keep your waist below half your height. For 170 cm that means under 85 cm. It uses one measurement and is easy to remember.
| Height | Half of height (waist guide) |
|---|---|
| 150 cm | 75 cm |
| 160 cm | 80 cm |
| 170 cm | 85 cm |
| 180 cm | 90 cm |
A rule of thumb, not a medical limit. Age, ethnicity and health history can change what is appropriate.
Common mistakes
- Measuring over thick clothes, which adds centimetres to both numbers.
- Pulling in the stomach, which makes the waist look smaller than it is.
- Tape not level. A tilted tape reads longer.
- Mixing units, such as a waist in inches and a hip in centimetres.
- Using different spots each time, so changes you see are just noise.
Questions people ask
What is waist-to-hip ratio?
It is your waist circumference divided by your hip circumference. It describes how your body fat is distributed, with a higher ratio meaning more weight carried around the middle.
What is a healthy waist-to-hip ratio?
The WHO flags abdominal obesity at 0.90 or above for men and 0.85 or above for women. Below those numbers is generally considered lower risk, though it is only a screening guide.
Where exactly should I measure my waist?
At the narrowest part of the torso, usually just above the belly button, or halfway between the lowest rib and the top of the hip bone. Stand relaxed and breathe out normally.
Is waist-to-hip ratio better than BMI?
It answers a different question. BMI compares weight with height, while WHR shows where fat is stored. Many researchers find central fat a useful risk signal, so the two are often used together.
Do I use centimetres or inches?
Either one, as long as both measurements use the same unit. The unit cancels out when you divide.
Can I use WHR if I am an athlete or pregnant?
It is not designed for those cases. Muscle build can change hip and waist size, and pregnancy changes the waist for obvious reasons. Ask a health professional instead.