There are three very common myths about the hourglass body type.
Hourglass (X) means big breasts. False. Actually you can be average and be hourglass.
Any woman with more than 10″(12″) difference between bust and waist and almost equal bust and hip measurement is hourglass. False. You can be pear or rectangle with such measurements. Or you can be hourglass despite the fact that your have less than 10″ difference (petite frame with broad shoulders and hips).
Any garment looks good on X because X is the ideal body type. That’s not true. Actually there are a ton of limitations if you want to look your best.
X tends to look bulky and frumpy in wrong clothes.
What is important is not inches or centimetres, it’s silhouette (profile should be considered, too, but it’s completely different story). The most accurate method of identifying body shape I know described in this post (BTW, if you happened to be pear shaped, I highly recommend the blog). I want to accentuate that breast size isn’t very important for silhouette. It definitely affects fit and it should be considered, but shoulders are more important for styling.
So slim torso, narrow shoulders, waist ~ underbust and curvy hips = pear.
Note that 26J girl most likely is pear or very slim rectangle.
More massive torso with quite broad shoulders, nipped in the waist and curvy hips = hourglass. True hourglasses tend to need larger bands even if they are slim.
Large bum doesn’t count for curvy hips, it’s completely different story.
Shoulders almost equal hips and underbust ~ waist and streamlined silhouette is rectangle. Slim rectangles usually do have a waist. And it could be 12″ difference between bust and waist for larger busts, and nice bum could be responsible for even bigger difference between waist and hips. But it’s still rectangle. Outfit accents should be in totally different places than for hourglass shape. E. g. imperial waist tend to look gorgeous on rectangles with average to large breasts and it’s total disaster on hourglass.
If shoulders are broad and hips are not curvy it’s V shape or inverted triangle. And again, slim triangles have a waist, but there are no curvy hips. Band size tend to be bigger for the same BMI.
As you can see, band size identified correctly could give some hints about body shape, because bigger band size correlates with broader shoulders for low BMIs. For higher BMIs it’s less reliable: it’s not only about skeleton structure as for low BMIs, it’s also about hormones etc. It’s possible to have different body types in different BMIs, but usually we stay the same body type in any weight.
I want to accentuate that there is no ideal body shape actually. Women of any shape can be beautiful, it’s more about how to create outfits which are in harmony with a body. I strongly believe that clothes shouldn’t work against body. I don’t think that we should try to pretend to be another body shape. When pear shaped girl hides her beautiful delicate arms and collar bones under something bulky trying to pretend hourglass and calls it balancing it makes me sad.
I’m more experienced in dealing with hourglass body type, so I concentrate on it, but please don’t take this as discrimination.