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Patternmaking: Bra Cups

The thing about bras is that they’re very particular – the fit varies with almost everyone. Two women may be an A cup but the way the weight is distributed within that A cup is different. One women may carry the weight closer to CF while the other woman carries the weight closer to her side. One woman may protrude more while the other woman protrudes less. And that’s what I’m going to talk about today – projection.

Projection is needed for any 2-dimensional piece of fabric to fit the 3-dimensional human figure. Projection can be achieved through shirring, darts, or curved seams and in bra cups, it’s usually achieved through curved seams. If the curve of the cup is increased, the line becomes longer (a curved line is longer than a straight line) and there will be more projection. The same holds true for the opposite.

Projection almost always causes fitting errors with bras. When I sewed my first bra, using Pin-ups Girls Classic Bra, the bra band fit but the cups didn’t. I have small girls and the curves on my bra cups needed to be reduced, like major. As shown in the diagram above, I reduced the curve from bust point (usually at the halfway point of the curve) and tapered to 0″ at the sides.The lower cup of a bra is again, almost always more curved than the upper cup (think of the curve on a princess seam – the side front panel is more curved and eased into the CF panel, which is almost straight), so I reduced the curve on the lower cup more than I reduced the curve on the upper cup (3/4″ for lower cup – 3/16″ for the upper cup).

I reduced the curve to fit my less-than-endowed girls but if you’re girls are more endowed, increase the curve to increase projection and provide more room within the cup. Be sure to walk the two pattern pieces – lower cup and upper cup – after adjusting the curve. Like I wrote above, reducing or increasing the curve on any line will change its length. You want to make sure the two pattern pieces match up after the pattern alterations or as least maintain the same relationship (length of lower cup might be longer than length of upper cup because it has ease built into it).

The location of the curve can also be adjusted for women whose girls don’t sit in the center. If your girls sit closer to CF or sides, the shape of your cup pattern will be more curved where your fullness is – the curve on your pattern won’t be centered at the center of the pattern. Does this make sense?

Reducing the curve of the lower cup can also be used to “flatten” the appearance of your girls. Some women don’t like the Madonna, cone-breast look, and this correction will make the girls appear rounder and flatter instead of projectile.

Bras are particular, yes, but they’re not hard. Your girls will differ from the rest of the girls, I assure you, and that’s why I can’t stress enough how important a mock-up bra will be. Until you make a sample garment, you won’t know where to eliminate or increase the curve of your bra cup pattern.


  1. Reply

    Rochelle New

    Good to know! I’d love to be able to sew my own underwear some day. I feel like my bra size is near impossible to find, and when it is found, it’s expensive.

  2. Reply


    This is so informative and comprehensive. Thank you for explaining bra cups in such a great way. I’m starting to dip my toes in lingerie construction and this will definitely come in very handy.

  3. Reply

    the Garment Farmer

    awesome info. Thanks Maddie. and I love all the “girls” talk πŸ™‚

  4. Reply

    Ruffles Gazebo

    thanks for this!! i made my first bra not too long ago after doing a short bra making course. It was just a general mock up, never meant to wear it, but the projection was WAYYY to much haha. cant wait to have time to make some more, i bought some kits online and they are so pretty πŸ™‚

    • Reply


      Where did you take a bra making course??!? spill!

  5. Reply


    cool post, Maddie! I have done much like you did on my bra patterns. It’s all about volume, and where that volume goes… πŸ˜‰

  6. Reply


    Good to know! I haven’t made any bras yet, but I’m considering it as a future option– I’m getting really tired of paying $20+ for a bra that only holds up for 6 months and then the cups start getting all weird. And that’s for the plain, unfashionable ones! (Just out of curiosity, when you have the seamed cups, do the seams show under knits? I wear a lot of knit tops, so I’ve been doing the seamless foam cups for awhile, but they just don’t seem to hold up!)

  7. Reply


    Once again, Maddie, super informative! Thanks! I have yet to tackle my second bra after making the Pin Up Girls Classic bra – the band fit but the entire cup was way WAY too small and I’m a bit stumped as to what size I should be sewing… so it just sits and waits…

    • Reply


      Sally, if you ever need help adjusting the pattern, I’m only an email away. I’d love to help!

      • Reply

        nafees atiya

        hi,anybody send me the pattern that how i attach bra cup in busty gown…plzzzzzzz

  8. Reply

    Heather Lou

    I just bookmarked this as I am going to get around to making a bra one way or another… thanks for the (as ever) clearly articulated and new-to-me info! You da best!

  9. Reply


    Thanks so much for this informative tutorial! I am exited to try sewing a bra and goodness knows this will help!

  10. Reply

    Amanda Russell

    I find this so fascinating, Maddie, because it’s absolutely true, and something we ALL have encountered at one time or another with RTW bras. I found the experience of drafting the cups for my bombshell dress very enlightening, and I discovered the need for changing the curve as you describe through the draping/muslining process.

    It excites me to think of taking this knowledge, and the advanced knowledge you are discussing here, of manipulating the curves to get an exact fit or a particular look, to work towards making perfectly fitting bras… how wonderful! πŸ˜€

  11. Reply


    Reading up on your bra fitting… it’s nice to have a lady with some smaller um, ladies who knows what adjustments I’m going through! Can’t wait to see your pattern!

  12. Reply


    Finally, someone who understands. I’m not talented enough to make my own bra but a made to measure well crafted bra sounds like heaven. There is hope. Thanks πŸ™‚

  13. Reply


    I need more help:( I have one side much larger than the other. I can’t just use a one pattern. 34d on one side and maybe b or c on the other? Projection is toward the outside.

    • Reply

      Maddie Flanigan

      It’s completely okay to adjust the pattern so that the cups are two different sizes. That’s the point of sewing your own clothes/lingerie – so that you garments, including bras and undies, fit your UNIQUE body. What do you mean by your projection is towards the outside? Do you mean your bust points “point” east and west (outward)?

  14. Reply


    Thanks for this information, I just needed the cups tweaking but didn’t quite know how, this helps, thanks.

  15. Reply


    Hi, I want to cut my polyfoam seamless bra cup (the top, to lower the height)…but I am scared to. I have only scissors but hear it is okay to cut with scissors it is is less than 1.5″ thick…plus I’ll be adding lace to I guess imperfections will be hidden.

    I am more concerned about the stretchy lining that is stretched over the foam…if I cut it…I can stretch it back over and sew it in again, right? Right now it is super-glued by the manufacturer…otherwise I’d have just undone the stitches and reused the additional material.

  16. Reply

    Terry B

    Hi, I have a very unique problem…I have had breast reconstruction and nothing fits. I am a sewer and am ready to give this a whirl. My breast reconstruction has resulted in a flat breast, meaning the cone shape of the breast is flat, imagine your areola not having any projection so the 2ish inches are flattened down. Any fitting suggestions?

    • Reply

      Maddie Flanigan

      Hi Terry! Thanks so much for reaching out to me; I love hearing from all my readers. I apologize about the fitting troubles you’re having. Although I haven’t had reconstructive breast surgery, I am flat chested, so I understand the challenge. I don’t mean to sound pessimistic, just realistic, when I say this. Darts are meant to give shape to a garment, and if you don’t have that shape, then don’t wear it. I came to that conclusion a long time ago and wear a lot of knit blouses or tops with no shape. Have you seen Grainline Studios Hemlock tee (it’s a free pattern)? That’s my go-to silhouette. Work with what you got, don’t fight it because you’ll lose.

      Again, I don’t mean to sound like a negative nelly. I don’t want to lie to you, I want to provide you with a solution.

  17. Reply


    I’m about to attempt my first bra cup pattern for a bustier-style swimsuit and this was SO helpful! Thank-you! πŸ™‚

  18. Reply


    This site is so informative! I just finished making my first bra – Pin Up Girls Classic – and the band fits wonderfully but the cups are too small. I really don’t want to spend additional money buying the next size pattern (one of my girls needs to increase by at least 1, possible 2 cup sizes; the other side is fine). Is there a specific amount of curve I need to increase the pattern by in order to increase a cup size, or is it hit or miss? Thanks for the help!

    • Reply


      You should have several sizes in that pattern, so you don’t need to buy another one?

      • Reply


        The pattern I have goes to 38D, and I need to go up from there. The 38 band fits well, but the D cups do not.

  19. Reply


    I really like your explanations here – especially the bit about where fullness may be distributed. I think that’s something I’ve been missing in my adjustments so far. Thank you!

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