Hi All!

Underwires. It’s a big topic, and I hope that I can shed some light on it, to take some of the mystery out of bra-making!

Since this is my first theory post in Bra-A-Week 2016. I want to start off this post by saying: there is no universal right or wrong, everything is a matter of preference. Bra-making and bra fitting is a very intimate and personal thing, and everybody has a different way that they like to make and fit their bras, and I’m happy to help by sharing my opinions and things that I’ve learned in my bra-making experiences and I hope that you’ll leave your opinions and experiences in the comments too πŸ™‚

The Basics:

Underwires are meant to help support and distribute the weight of breast tissue into the band of the bra. They also help to give more shape and lift. Underwires should not be uncomfortable or painful.

Underwires are generally made of steel, and can come in different gauges (thicknesses) that have different strengths and levels of flexibility. The thinner the wire, or the more flexible the wire, the less support it will give, and the more it will bend from its original shape. The thicker/stronger a wire is, the more support you will get and the more it will hold its shape. I prefer to use a wire that is thicker and stronger for more support, shape and lift. I use a 24 gauge wire, and that is the gauge of wire that I offer in my shop.

Now the more challenging part: fitting an underwire.

Underwires come in different sizes, lengths and shapes.

The size and the length of underwires are pretty straight forward.

SIZE: Size of an underwire is about the overall diameter of the breast and is often calculated by your band and your cup size, as your cup or your band size increase, so will the diameter or your wire. In the industry they have pre-determined the diameter of a breast for each size of bra (e.g.. 34C is a 36 size wire). As we know- this is a ‘standard measure’ and just because you have a certain cup and band size, doesn’t mean that you will be that wire size- and we have the luxury in making our own bras to find the wire that fits our own unique body, instead of going by a standard! πŸ™‚

LENGTH: Length refers to the length of certain type of wire (surprise! lol). Generally speaking, length will refer to the length of the wire at the centre front, because this length will indicate the height of your neckline, wether you are making a plunge bra, or you want something more full coverage at the centre front.


Now the shape of the underwire can take a little bit more thought and examination. This is something that I haven’t seen talked about very much online, and that I’ve had to figure out through many fittings and talking to people who struggle with underwires. So what I’ve generally found is that breasts come in different shapes. And when I say different shapes I’m talking about the shape of the crease between breast and body where your underwire should be sitting.

I’ve found that people can be more ‘tall ovals’, ’round’ or ‘wide ovals’- somewhere on this continuum of shapes.

(please forgive my mediocre drawing skills, I think the tall oval and the round could have been little more distinct- but alas, it’s good enough to get the point across)
People can fall in a lot of places on this line, but I find that the people who have the most challenges fitting underwires are the people who fall more to either side.
People who have a tall oval shape, are generally more likely to have larger cups on a smaller frame (because that’s the only way they fit!), generally there is not much space between breasts and they need a wire that is deeper with long arms and goes up straight at the centre front. So if they have a wire that is too shallow and splayed, they will have to be spaced too far apart, they won’t get the support that they need, and it won’t sit flat against the chest in the centre front.
On the other hand, people who are more of a wide oval shape are more likely to have smaller or shallower cups, spaced further apart. They might find that the regular underwires that fit width-wise across their breast have a gap at the bottom where it extends below where their breast tissue ends, and they find that the arms of the wire are too long at the centre front and under the arm. They need a wire that is more shallow, and splayed to fit comfortably.
This is the main goal that I’ve been working on with my wire selection in The Emerald Studio: finding different shapes of wires to suit all the different shapes of women πŸ™‚ Β So I will show you, using the wires I have available, which shapes I find help for different shapes of breasts. *these are all wires that I have available, but these shapes, styles and fitting elements are things that you can look for in any underwire*


Here are sample wires all in the same size (38) to show the difference between them, and how they are meant for different shapes.

The Bliss is meant to help women who are the “Tall Oval” Β (you can see how the tall oval would rest well in this wire)

The Round is meant to help women who are a more round shape (you can see how a round breast would sit well in this wire)

The France is meant to help women who are a more “Wide Oval” Β (you can see the wide oval sitting well in this wire)

The Plunge is generally for the tall oval or round shape that is looking for a plunging neckline.

You can see from the shape of these wires, how the breast is meant to sit in them, and how some would be better shapes for different shapes of breasts

Here is a closer breakdown of each type of wire:

The Bliss

You can see that The Bliss wire has ‘deeper shape, and is slightly more narrow in width, and at the centre front it is very vertical, which means that you can bring the two wires very close together in the centre front for women who find that they have no space between their breasts. This wire also has a little bit of the roundness reduced at the outer bottom edge, to help push the breast tissue out from under the arm and towards the front.

The Round

The round wire is a very standard shape of wire. It is, as the name would say, very round, with a more gentle amount of splay at the centre front. This is a really good wire for people who have a very round crease where their breast meets their body, and generally these ladies will have fairly proportionate breast-to-frame ratio.

The France

This wire was inspired by a good friend, who had a hard time finding any wires that would fit her shape. This is a very shallow wire for women who find they are more of a ‘wide oval’ shape, you can see it has a gentle curve at the bottom, and the arms are very splayed. The arms of the wire are also quite short under the arm and at the centre front to suit this shape.

Now the France wire can be worn by women who are the wide oval shape, and they will fit in a similar way to a round wire or a bliss wire on the women who suit those shapes. But the France wire can also be worn by women who have other shapes, who want a wire that is much lower under the arm, for different styles of bras, or more relaxed fitting bras (that’s how I like to wear them, even though I’m not a wide-oval). They are a more versatile and relaxed wire that can suit different shapes and sizes.

The Plunge

The Plunge is a good example of a different length of wire. You can see from the plunge that the underarm edge is similar to the Bliss and the Round wires, but it is much lower in the centre front, to suit the plunging neckline styles.

Because of the height of the underarm edge, this style might not be the best for a ‘wide oval’ shape, since the underarm would sit too vertically and high, but it is a great option for plunging necklines for tall ovals and round shapes.


Now that you know a little bit more about underwires, I’ll use myself as a case study, since I’ve worn all of these underwires, and know quite a bit about my shape.

I find that my shape is somewhere between Round and Tall Oval. I can comfortably wear both the Round and the Bliss wires, but I find that the Bliss wires are more flattering for me: as you can see from this photo from Bra Theory September. (Bliss wire on the right of the photo is a slightly nicer shape for me)

I’ve also shown the France wire in my latest bra. Now I’m not the standard ‘wide oval’ shape for this wire. But you don’t HAVE to be that shape to wear the wire, I wear this wire as a much more relaxed fit, low under the arm, lower in the front. You can see that it’s not giving me the same shape as the Bliss or Round wire and offers less support for my shape, but it is pretty for more dainty lingerie looks πŸ™‚ Β and would also be comfortable for more lounge-bra styles.

And finally the Plunge, you can see that I’m getting the same amount of support and shape under the arm as I would wearing a Bliss wire, with the higher under arm- which is helping to push all my breast tissue forward (yay for cleavage!) and then the wire is nice and low in the front for that plunging neckline πŸ™‚


Underwires take a little bit of trial and error before you find the perfect ones for you. And if you don’t like underwire at all, you don’t even have to wear them, there are nice no-wire options too! It’s all about trying new things and finding out what works best for you.

What are your underwire preferences? Did you learn anything new from this post?

Let me know!

Happy Sewing

xo erin


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  • Michele


    I have found that the bra that fits me best is a plunge cup (seems to match BMS short wire). But these don’t appear to be available in Australia and postage from BMS (or here or anywhere outside) is pretty steep.

    The shape of the outer end of the arm appears to be more straight than a regular round but would it be possible to make a plunge wire by cutting a round wire down or is that wishful thinking?

  • Mkikoo

    Very useful topic – Now that I know that I am a wide oval, with a wire size that seems very different from my bra size, can you suggest a bra shape pattern to match the wires ? It is very difficult to get an idea from a drawing and I feel my first attempt is a mistake since the pattern suggest L (long) wires…Do your black beauty allow using low wide wires ? Being very very short my upper bust is also way shorter than average and RTW are either too big or hurt me with wires. Plus, medium bra coverage turn into full coverage on me, so it shows under summer dresses. Thank you for helping.

    • Emerald Erin

      Patterns are the difficult part, I only have one underwired pattern available and it is suited to the Orange wire. I don’t have any patterns for the France or Carmen wires at this time, it will be something that you need to make alterations for.

  • Sue

    This is absolutely right.
    I have been struggling with underwires all my life until i discovered i have to bend them to make them flatter (more France shaped) Last month.
    I was frustrated when i couldn’t find anybody online talking about this, and no bra companies understood.
    I was so confused as to how bra companies seemed to think breasts were little half oval things placed on the front of your chest, That’s what the normal underwires seemed to imply anyway.
    Thanks a lot!

  • Trudy W.

    Dear Erin,
    This is a very helpful post. Are the names of the wires your own? Or are they an industry standard?
    I'd like to know what to look for when shopping for wires both online and in NYC.

    So far I've only used the Long wire that Bra Makers recommends for their Pin UP Girl Classic Bra.
    I like the quality of their wires very much.
    Which of the above wires is the Long wire that BMS supplies?

    And are you able to speak to the which BMS wires are the equivalent the Bliss, Round, France (if any) and Plunge?

    Thank you.

    • Reply

      Hi Trudy, The wires are my own names that I've given them, I personally don't know of any 'standard industry names' for underwires. I cannot speak to other shops and their supplies. All I can tell you is that the underwires I supply are top quality underwires, made of galvanized steel in a 24 gauge, which are very supportive. Thanks for your comment, Erin

  • Reply

    Very helpfull Erin! Especially the photo where you point out the difference between the Bliss and round wire. I am definitely a Bliss person!
    Thanks for this.

  • Reply

    It is nice to see you are offering different wires! I have learned about these differences the hard way myself too.
    Next to the bust shapes you mentioned, I have often observed another issue which has to do with bra fit, bra sizing and underwire shapes: The relation between the volume of the breast and its surface on the chest wall. Standard sizing assumes a linear relation but the truth is different: For example, women with larger band sizes and small breast often need a B or C wire but very shallow cups.

  • Reply

    Can you get a "bliss" plunge? The RTW bras that I wear have the most AMAZING, PERFECT wires in them. And that wire looks a lot like the bliss, but with a VERY low center (~2" for a 36E). On your plunge, the wire splays out just a bit in the center, but on my ultimate bra wire (the ones from the Elomi Betty, if you're curious) doesn't splay out at all. After these bras finally give up the ghost (any day now, if we're being honest) I plan to pull them out and sew up bras to put them in, but eventually I'm sure the wires will wear out too, and I want more than three pairs anyway.

  • JessieRoo

    Super helpful post on a topic I've never seen anyone else write about. Having photos of how each type of wire fits on an actual body illustrated your point so much better than a schematic would have. I haven't tried my hand at bra-making yet, partly because I didn't know where to find the wires that would fit my body comfortably-those really deep and round ones always slip downward and dig into my ribs when I bend over, plus there's always a huge gap where they dip down at the center front so much so that even a heavily padded push-up style does basically nothing for me.Obviously I need to get my hands on some of the fancy-sounding France wires.

  • Reply

    Great post, Erin. If we know our size in one of the wires, would be buy the same size in the other styles?

  • Sheila

    Thank you for this post! The fit photographs are extremely helpful and have given me a lot to think about.

  • Reply

    Thank you Erin, this wire stuff has perplexed me. Specifically on selecting the right size wire for my pattern. It seems there is a large variance from supplier and bra designer alike. I haven't had much success yet with my underwire bra making….but I guess I need to keep making them to get better πŸ™‚
    Do you have a way to subscribe to your blog so I get an email when you post? My email is genevieve1designs at gmail dot com. Thanks!!

    • Reply

      Thanks Geni! Wires can be tricky! I'm hoping to find the best wires for all different bodies, then come out with a line of patterns so it's much easier to match your supplies to your patterns! But bra-making is a labour of love that takes practice! πŸ™‚

      Also I added your email to my email subscription service! You should get a confirmation email soon πŸ™‚

  • Din

    Hi Erin,
    This is so useful! I had no idea how underwires related to the shape of your breasts. I bought some underwires from Etsy and I think they're somewhere between Bliss and Deep Plunge. Anyway, now I know what to look for!

  • Reply

    Great post, Erin!! I always learn something new thanks to your bra theory posts! I don't have that many wire options at my local store, so it's nice to know that they exist. There's really a wire for everybody! πŸ™‚

  • Reply

    Thank you for this information. As my figure has expanded I have had to stop wearing underwires as with the larger sizes the wires poke my arms. I haven't selected a pattern but I need something with a DD cup and a substantial band in the back to smooth the bulges a bit. Any suggestions?

    • Reply

      Thanks Linda! From the information you've given me, I'm not really sure what to recommend. It's hard to know without seeing you in person, or having you try the wires yourself. It could be the case that you increased in cup size, but didn't increase in wire size and the underwires that come in the larger bras are too big and poking. So it could be the case that you just need a smaller wire, or possibly the more narrow wire like the Bliss would be a benefit too. I sell underwire fitting packs in my shop where I send three consecutive sizes of the wire to see which one fits the best. Hope this helped a little!

  • Reply

    Thanks for this post and all the information. I definitely think the Bliss wire would be perfect for me. I wish it went up to a size 60, though! πŸ˜‰

    Any advice on how I can bend the extra long round wire into a more blissfull shape? Or….would you be able to get the Bliss wire in a size 60? I will be a very very loyal customer of those. πŸ˜‰

    • Reply

      Thanks Andie, I'll look into getting the bliss in a size 60 πŸ™‚ see what my inventory budget will allow πŸ™‚ I'll let you know!

      As far as bending wires goes- I generally don't recommend it, because they are super tough to bend, then getting them symmetrical is tricky- and I find that they do have a bit of memory too, so they tend to drift back to their original shape. I don't have too much experience bending wires though.

    • Reply

      Definitely let me know. I'll buy all of them. Hahah. πŸ˜‰

      I've sort of tried to bend them with no success. I agree they are definitely too rigid and go back to their shape really easily. Oh well! Crossing my fingers you can get size 60 Bliss wires. πŸ˜€

  • Reply

    Thanks for sharing all this interesting wire info! When you shared the post about the france wire earlier, I thought it might be something that would work for me. I definitely have what you call the wide oval shape, which seems to be a good description for my problem! I have struggled for a long time to try to buy bras RTW, and am so much happier now that I have been sewing them. I have typically been cutting down a regular/round wire at the center front to alleviate poking problems. I'd like to give the france wire a try, but I wasn't sure what pattern to use or how to alter a patter to work for that type of wire. It looks like it has a much shorter length along the wire than the others. Any thoughts?

    • Reply

      Hi Megan! I'm so glad that this post helped! There isn't a pattern currently out for this wire (maybe one in the future πŸ˜‰ ) But what you can do right now is take your current pattern that you're using and measure the France wire along it (the best way to do this is to make sure that the centre bottom of wire is a the centre bottom of the cup, then walk it towards the centre, and towards the underarm). Then you can mark where the wire ends and trim down your cups and frame to that point, and re-draw your neckline and underarm to match the new height of your wires. I will also say that this could be a fairly large alteration- so make sure you don't use your favourite lace to test this out!

    • Reply

      Thanks Erin! I'm a little on the fence about the france wire since I do like the height of the regular wire under the armpit to sort of smash all that fluffy stuff forward πŸ˜‰ I'm worried the frame would be a little too low and not give enough shaping since my breasts tend to splay outwards towards the side. I definitely think I should give it a try at some point though, especially since it seems like it will be more comfortable. Thanks!!

    • Reply

      If it's only at the centre front that you feel it needs to be lower, a plunge wire might be a good fit for you! πŸ™‚ Something to think about πŸ™‚

    • Reply

      Yes, I have thought about that! I have a whole supply of round ones that I need to get through first, since cutting them down isn't too hard πŸ˜‰ I do get an empty spot in the bottom of my cups where the wire is most rounded because it doesn't follow my shape, so that would be one thing the france would fix! Thanks for all the info.

  • Reply

    Great post, it's good to see the many different wires.

  • Reply

    Great post, Erin! The photos really show how the wires give different shapes. Until I found wires that worked for my Omega shape, wires were always uncomfortable and didn't give the support I needed. I'm using Flexible wires now and they're working well.


  • Reply

    A very helpful article, as I had no idea about the differences between the wires. Your research will be so helpful to so many people! Thanks.

  • Reply

    Great post Erin! The more I read about about the Bliss wires the more I really think I need to give more vertical wires a go – and the more I really want to order from your store! Shipping to Australia is such a killer though πŸ™ Still, it's starting to look like I am almost definitely taking a trip to Canada at the end of this year – so maybe I'll be able to come and pick some up for myself! πŸ˜€

    • Reply

      Thanks Maddy! And are you really coming to Canada!!! That is AMAZING!!! Please come and see me πŸ™‚ You always have somewhere to stay in Ontario πŸ™‚ πŸ™‚

      • Toni

        Hi Erin, I am another from australia who is looking into making my own bras due to the issues I have in finding bras that fit. I am also definately more of a wide oval but also find that I need to pull them forward up under the arm which is probably in part due to wearing firm fitting sports bras mostly due to some of the work I have done (jillarooing) where I have needed good support even though I am only a quite small cup size (A). Thankfully now I am working in retail where I dont need the support anywhere near as much but it is still not easy finding good fitting bras.

        • Emerald Erin

          I think with underwires it’s best to try a couple different ones, because you never know how they will fit you when they’re on the body, especially because some people like tight bras that spring the wire a lot and some people like loose bras that don’t. A good starting point is my Orange wire though, because it’s really smack in the middle of fit types πŸ™‚

    • Reply

      Yes!! It's still in the planning stages but I am very very excited about it! I'll definitely be in contact once I'm more certain about what I'm doing :)))

    • Reply

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  • Reply

    so timely…I was just tracing off patterns and find my wire is too long for designated sizes–I think I'm a Bliss….I have to adjust patterns to accommodate wires πŸ™ This is very helpful…I'm going to conquer bras this year!!!!

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