Waist to Hip Ratio Survey Findings Part 1

Standard Disclaimer: When I write a post like this, I think about the numbers and proportion.  I would be heartbroken and shocked if my words were taken as a value judgement of some kind.  I’m just playing with numbers here, seeing what turns up.  I don’t care what size someone is, I just want to dress both the body and the person inside the body well.

When I set up the form for the Waist to Hip Survey, I set a goal of 300 entries and thought myself very ambitious and figured I might hit that number in a few weeks or a month.  By Thursday, we had surpassed 300 and I realized I better start digging around in the numbers to see what turned up.  I’m leaving the page open and in the sidebar for now because I have an even more ambitious number of sets I’d like us to reach: 1000.

I’ve been curious for quite some time about the relationship between waist and hip measurements and the resulting ratios, and how that might apply to pattern sizing and drafting.  I do like to work through little puzzles like this to find my own answers when possible.

You can find the ratio by dividing the waist measurement by the hip.  If you’re mathematically minded: ratio=waist/hip.  The bigger the difference between the waist and the hip measurements, the lower the resulting ratio number.

The basic idea I wanted to test on real measurements is this: As waist size increases, the waist-to-hip ratio decreases.  That’s pretty basic, but I wanted to check it.    I  also had a few secondary questions:

  • .7 is considered the “ideal” ratio for waist-to-hip measurements, but what is the commonest ratio?  
  • How much does the waist to hip ratio decrease as size increases?
  • Can I find body shape types from only these numbers?
  • What ratios do some common pattern companies use?

I’ll show you what I found, question by question.

First I’ll run through the limitations of my survey.  All numbers presented come from a sample size of 359.  I am still greedily accepting measurements for the survey, but for the sake of this post I stopped on Friday morning at 359.

Secondly, all measurements are self-reported, which means there may be some variation on measuring tape tightness and whatnot.

Thirdly, the data set is limited to people who sew.  I assume.  I write a sewing blog and posted about this survey in sewing channels.  It would be interesting to explore how sewists’ measurements relate to the rest of the population, but for now we’ll leave that.

And finally, I work in both cms and inches.  I use cms in my spreadsheets because the decimal points make more sense than a fraction in that form.  Let me know when I forget to write both.

As waist size increases, ratio decreases

This is true, and it’s common sense.  A few months ago, I wrote about elements of good fit.  One element of good fit involves fat/muscle distribution on the body.  Another element involves bone structure.

A waist measurement is a “fat/muscle distribution” measurement.  You don’t have waist bones.  Waist measurements also depend on the way your guts are put together and the hormonal cocktail flowing through your veins, but that’s not within the realm of fitting clothing so I don’t know much about it.

A hip measurement may be a mixture of the two types.  Someone with relatively low body fat may have a wide pelvis.  Another person with a relatively small pelvis may be carrying greater mass in the hip area.  To compound the hip problem, mass may be distributed more toward the back, toward the sides or distributed evenly around the hips.  This makes the hip measurement somewhat “less reliable” from my point of view (too many variables), though when I pick a pants pattern I use my hip measurement to choose the size.

This shows the breakdown of the waist measurements I received.  X=”waist measurements” so the commonest category is those measurements that are greater than 70cm but less than 80cm.  That is, the commonest category is “greater than 28″ but less than 32″”.

And here are the hip measurements.  In this category, “greater than 100cm and less than 110cm” was the largest category. To put it another way, the commonest range lie at “greater than 40″ but less than 44″” through the hips.

I separated the measurements into “60’s, 70’s, etc” and found the average ratios associated with each waist measurement.  As expected, the ratio decreases as waist size increases.  This is broad, but it shows the observation was correct.  Ratio does indeed decrease as waist size increases.  In inches- 24″, 28″, 32″, 36″, 40″ through the waist.

What is the commonest ratio?

By the numbers I have, the commonest ratio is greater than .75 and less than .8.  Combined, the commonest ratio is greater than .7 and less than .8.  Again, that’s pretty broad.

What do you think?  I have some other questions to explore, but when I tried to put everything into one post it became very long reading indeed.  Tomorrow I’ll look at my other questions: Can I predict the rate of ratio change from one waist measurement to the other?

What do you think so far?  Would you like for me to ask the numbers some questions? Please, clever people, pick some holes.  Also, I made a chart of ratios a few pattern companies use- which company would you like to see?

Tune in tomorrow for part 2 of the numbers breakdown and my idea for a shapes survey…  And then it’s time to focus on this month’s hack!  I’m inspired by collar shapes from the early 50’s and Tanit-Isis’ unwitting challenge to use polar fleece.  I can’t stop thinking about working with it now she’s put it in my head, it should be very interesting!


26 comments

  1. Makes sense. For what it’s worth, anything under .8 is the generally accepted “healthy” waist-to-hip ratio too. My additional question would be how the abdomen fits into all this in terms of fitting pants. You talk about mass being distributed around the back, the sides, or evenly around the hips, but let’s not forget those who carry their mass up front. Great research!

    • Yes, there’s the front, too. I don’t know much about biology, so I can’t really hazard an opinion on .8 being the “healthiness point’….

  2. Interesting… I know its not really possible, but I would be curious to see how the ratio changes on individual people as their measurements increase or decrease.. eg. my ratio is smaller than your found norm for my waist size, if I lost weight, would it get smaller? If I gained, would it increase? Or do we as individuals stay within a certain ratio range? Hmm.. not a suggestion, just my brain working!! Very interesting numbers you’ve found, very interesting indeed.

    • My ratio stays the same as I gain and lose weight, but I have a pretty well-defined waist to begin with. Whether someone else would change, I really couldn’t say.

    • My ratio actually gets smaller as I gain weight, because I tend to gain weight only in my hips and thighs.

  3. I’d be interested in seeing what the ratios for the pattern companies; big 4, modern vs vintage. Also, how did waist/hip ratio change with the style eras; 40’s vs 50s. etc. Knowing what the ratio trends of pattern companies as whole are, helps decide which makers dress pattern to buy by knowing if it will fit better.

  4. This may be beside the point, but there is a question about where the waist is located. What I mean is that in the medical area (i.e. for bmi calculations) the waist is defined — not as the smallest part of the torso — but as a certain distance from the navel. I can’t remember what it is, maybe 2 inches above or something like that. For someone like me, who is fairly short waisted, there is this weird discrepancy between the medical waist and the ‘dressmaker’ waist measurements. (I tend to think that the medical perspective is wrong on this definition of waist, but anyway…)

    Coincidently, I have been thinking about waist vs. bone structure lately. It seems to me that a short waist results from a shorter rib cage and that this is often accompanied by a relatively narrower hip/pelvis width (in European descendants). The result, based upon observation, seems to be a less visibly defined natural waist. Well, a waist that does not usually lend itself to the cinched 1950s silhouette in any case. Conversely, a wider hip/pelvis would tend to result in a more visibly defined waist, so long as the ribcage is not atypically wide. These thoughts are based upon my observation in life sculpture classes I took years ago (as well as my own body). But maybe this is just a different expression of the mathematic ratio?

    ~Jen

    • Well, since this is not a medical blog, I’d say it’s definitely beside the point. :) As a dressmaker, I tend to use dressmaker’s measurements. Call me crazy.

      Just a shot in the dark, but I would think a shorter ribcage would help create a more defined waist. I suppose it depends on the relationship between the spine, the pelvis and the ribcage.

      I did not find any relationship between the hip measurements and the ratio. I did try, but there’s no relationship.

      • Not quite sure why I got on the bmi mini-rant there, but I’m so not a morning person and that’s my mini-excuse…
        My theory about the short-waisted rib cage was not well explained either. What I’m thinking of is a certain body type. By proportionally narrower hips I’m referring to what looks like higher hip bones. I think the pelvis is maybe kind compressed vertically compared to a body that appears to have lower hip bones. I can draw a picture in my mind of it, but not express it very well I guess. When the hip bones are tilted higher this also pushes the waist up higher. So you end up with a less defined waist regardless of torso/rib cage length. Long torso–maybe a subtle waistline, but with a short torso—a high waist (short waisted).
        Sorry I’m kind of babbling today.

        • I think I may understand what you’re saying. I’ve been reading some studies on waistlines and what causes them, some stuff on behavioral genetics and evolutionary biology, and also some research about hormone levels and bone structures… I haven’t really found much that directly relates to sewing, so I haven’t posted much about that here… But it’s interesting.

          A waistline, from what I can tell, is mostly a function of hormone levels and fat storage/muscle tone.

  5. Would you maybe like to show a XY plot of waist vs hip measurements? It would be a nice visualization in addition to the most common ratios you listed. Will there be clustering (indicating specific shapes) or much more spread? It is great that you collected this data and thank you for sharing!

    @Jen: I found that when I moved to the US the less defined waist occurred to me as something more common seen in Caucasian Americans as compared to Northern Europeans, but could be that I just recently started to pay more attention. (I have a long torso, defined waist and larger hips, so clothes shopping is frustrating if I want both to fit.)

    • I second the request for an X/Y plot! Just out of curiosity and maybe for that little thrill of knowing “that’s me way over here!”. This is all strangely fascinating to me!

    • No, there’s no clustering. I’ll put up the XY scatter graph tonight, I wasn’t sure if it would be interesting or not to y’all. I guess it’s pretty interesting in that it shows that all kinds of ratios exist at most sizes, but that’s about it. :)

    • I’m not so sure, Mona. I’m not talking about body fat, but bone structure. I have a very similar figure to my german grandmother – not much of a waist and a bit shorter-waisted too. I am just taller. However, my greek mom has a tiny waist, generous hips, a long torso & narrow shoulders. No way we can share clothes!

      • It’s well documented that higher estrogen levels in an individual make for a smaller waist in relation to the rest of the body. As female bodies age, estrogen levels decrease which is why “middle age spread” happens. Some body types simply have lower estrogen levels in general, which accounts for slighter figures with larger ratios…. I think hormones play a much bigger role in waistlines than bones.

        Start here:http://en.wikipedia.org/wiki/Female_body_shape#Impact_of_estrogens

  6. Fascinating! Apparently I am very typical in my ratio ;) which is interesting because I don’t “feel” all that typical… hmm.

    Also, Muahahahaha :)

  7. Picking up on the comments on relative short waistedness, or ribcage form, it would be interesting to see how the width measurements correlated with the height ones. So, for example, would waist to hip measurement have any bearing on ratio of waist to hip.

    • Maybe, but the question is a little too sticky for me to unravel. You’d be measuring bone structure in the height category, and both bone structure and weight distribution in the width category… I am not so sure you’d find much reliable correlation.. But it could be interesting…

  8. Pingback: Waist to Hip Ratio Survey Results Part 2 « 3 Hours Past the Edge of the World

  9. Very interesting! I came to your blog because someone posted a link to my Underbust Survey on another post and it seems like we’re really interested in the same things here.

    I know personally I fit in smack dap into “average” according to your results (well, my prepregnancy measurements, currently my belly is changing by the day!). However, pant fit has always been atrocious on me for two reasons:
    1. My hips measure 96cm but it’s all butt and no hips
    2. My waist measures 75cm but my torso is very straight so considering manufacturers tend to assume about a 5-6″ difference between waist and high hip measurement I have to size down quite a bit from my actual waist measurement.

    I’ve often wondered if there was some way to better study both the bone structure vs. fat distribution in terms of hip meseasurement, for instance. And have also thought high hip measurement was a more accurate determination of pants/dress size (well, assuming that one is not wearing high-waisted pants).

    Another point about your survey…. I would if there wouldn’t be much more variation at larger waist sizes? One thing that I found in my own survey was that for higher waist sizes and/or higher BMI’s there was a much larger variation amoung women.

    • I don’t have the survey in front of me right now (shh, I’m making a Circus..), but that is a very intelligent question. I’ll take a look when things quiet down closer to the holiday and let you know. :) It’s a decent sample, though, so it should be interesting to check out the variation… Off the top of my head, I remember greatest variation somewhere toward the larger side of medium… But I’d really have to go take a look..

      • Great! I can’t wait to hear more about it and especially see if the variation is truly large at the higher end. :)


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