Spilling out of your bra can not only be uncomfortable but unsightly, too. Bra spillage can create a bumpy “quad-boob” look under form-fitting shirts, and no one wants to risk having a wardrobe malfunction bending over to pick something up. Cup overflow and side spillage are never comfortable, so having a bra that fits well and offers proper coverage and side support is crucial.

Whether you’re dealing with your breasts overflowing out of the top of the cups or side spillage out of the side panels of your bra, don’t worry, there is help! Keep reading to learn what the common causes of bra spillage are and how to fix it.

Bra Spillage? Why it Happens and How to Prevent It

Why do I fall out of my bra?

Bra spillage is more common than you might think. The key to preventing it is by knowing why it happens. There are several reasons why your bra might not be doing the best job it can be.

Bra overflow happens when the top of the breast tissue doesn’t fit into the cup of the bra. This can happen for a variety of reasons or a combination of them:

  • Cup size. If you’re wearing a cup that’s too small the cups won’t properly cover the correct amount of breast tissue. This amount of coverage varies from style to style.
  • Band size. If your band is too tight it can cause the cups to stretch farther apart than they’re supposed to, resulting in the edge of the cups cutting into your breast tissue.
  • Breast type. There are several different breast shapes and not all fit into every type of bra. We’ll go over the different shapes and what styles suit them best a little bit later.
  • Uneven breasts. Most women have one breast that’s larger than the other with different degrees of severity. Some women barely notice the difference while for other women it can cause a problem when it comes to finding a bra that fits properly. When bra shopping you should base your fit on your larger breast. If there’s a large gap in the other cup you can always add an insert or some padding.

How do you know if your bra cup is too small?

If your breasts are spilling out of the top of your bra, this could be because you’re wearing the wrong band or cup size, or a bra style that isn’t suited for your breasts.

The best way to figure out what’s causing the problem is to measure yourself and make sure that you’re wearing the right bra size.

First, take your band measurement by wrapping a tape measure around your back and chest directly under your arms and just above the bustline. Round to the nearest whole even number. This will give you your band size.

Next, measure across the fullest part of your chest to get your bust measurement. You’ll then subtract this bust measurement from your band measurement. The difference in inches determines your cup size:

  • 1 inch = A cup
  • 2 inches = B cup
  • 3 inches = C cup
  • 4 inches = D cup

Add a cup size for every additional inch

What if you’re wearing the correct size but you're still spilling out? It’s time to take a look at your breast shape and bra style and see if they’re compatible with each other.

breast types and cup sizes to prevent bra spillage

How can I prevent my bra from spilling on the side?

Side spillage happens when the sides of your breasts don’t fit properly into the cups.

If you’re dealing with side spillage out of your bra, you might need a different cup size or perhaps a different bra style altogether that offers good side support for your particular breast shape.

Not every bra style will work for every breast shape. If your current bra style is leaving you with unsightly and uncomfortable side bulge, it might be time to invest in a new bra that offers proper side support and coverage.

There are bras that feature added side support panels for complete coverage. Other side support bras have different cup shapes that keep your breasts contained on the sides. Whatever the cause of your side spillage may be, there are bra styles that offer the proper side support you need.

Keep reading below for a breakdown of different breast shapes and the proper bra styles for each.

How can I prevent my bra spillage in the front?

If you are dealing with spillage over the top or front of your bra, this is likely a sign that you need a larger cup size. If your bra cups are too small, you will probably have your breasts spill over the top of the cup. Not only is this uncomfortable, but it also means that your bra is not providing the support you need. A properly fitting bra should have bra cups that comfortably encapsulate the breast tissue, with no spillage or gapping.

If you think you might be in the wrong size bra, we recommend having a bra fitting or taking your measurements at home to ensure you have the proper fit.

Breast shape and cup styles

There are many different breast shapes, and certain bra styles work better for certain breasts. Knowing what breast shape you have is helpful in choosing a bra that fits well and flatters your body while providing ample coverage and side support.

Here are the most common breast shapes:

Breast Types:

  • Asymmetrical: One breast is larger than the other. Most women have asymmetrical breasts to some degree with the typical difference being a half cup size or less.
  • Athletic: Muscular and wider with little breast tissue.
  • Bell Shaped: Slimmer at the top and fuller on the bottom.
  • Close Set: Close-set breasts have little to no gap in between leaving more space between the breast and the underarm.
  • Conical: More cone-shaped than round. Cone-shaped breasts are more typical of smaller breast sizes.
  • East-West: East-West type breasts have nipples that point outward.
  • Relaxed: More loose breast tissue with nipples that point downward.
  • Round: Round breasts are equally full on the top and bottom creating a round shape.
  • Side Set: Set farther apart with a wide space in the center of the chest.
  • Slender: Long and narrow, pointing downward.
  • Teardrop: Round in shape at the bottom but with less fullness at the top.


Popular bra styles and the breast types they flatter the most

Full Coverage

  • Cups that cover all of the breast tissue, and come in both lined and unlined styles
  • Best for: All breast shapes
  • Visit our Full Coverage Bra Collection

T-Shirt Bras

  • Seamless with lightly lined, molded cups. They come with or without an underwire. Perfect for creating a smooth look under tight-fitting clothing.
  • Best for: All breast shapes
  • Visit our T-Shirt Bra Collection

Demi Bra

  • Cut horizontally across the top of the cup like a balconette bra, but lower.
  • Best for: Bell-shaped, slender, or teardrop breasts as it helps to create a bit more fullness at the top of the breast.


  • Typically unlined and cut horizontally across the top of the cup; made to provide subtle lift.
  • Best for: All breast shapes, especially fuller types, however, this type is more likely to create cup overflow and side spillage if the fit is too small.

Push-up bra

  • These are padded with extra padding on the bottom of the cup to lift the breasts up and push them closer together creating enhanced cleavage.
  • Best for: All breast shapes, especially smaller or athletic types, however likely to create cup overflow and side spillage if the cup is too small. Push up bras with removable padding can be good for asymmetrical breasts.
How do I prevent bra spillage

Concluding Thoughts

No matter what breast shape you have, having a comfortable bra that fits well is key to avoiding cup overflow or side spillage. One of the most common reasons women deal with these uncomfortable fit issues is due to wearing the wrong bra size altogether.

If cup overflow or side spillage sound familiar, it might be time to re-measure your bra size or try out a new bra style that offers more coverage and side support. Regardless of what bra style you choose, make sure that you choose a quality brand and take proper care with washing your bras.

If you’d like to confirm your bra size, check out our measuring guide and Bra Size Calculator. If you need help finding the perfect bra, check out our Bra Finder Quiz and we’ll match you with bra styles you’ll be sure to love.

Having trouble with your bra straps falling down? Read our post for that, too.


About the Author

Maeve Gesualdi is a Fordham University alumna where she earned a Bachelor of Arts in Communications and Fashion Studies. Based in New York City, Maeve is part of the marketing team at Glamorise. Maeve regularly interacts with customers via social media and product reviews, as well as with influencers and models. She is constantly getting feedback on our products as well as gaining a better understanding of what women in our category struggle with and/or look for when searching for a bra. Aside from writing, she is passionate about all things travel and fashion.

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Author: Maeve Gesualdi
Last updated on: 7/19/23
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