In this guide, I’m going to assume that you’ve already mastered the art of finding your true bra size. You’ve measured yourself according to the guide, you’ve established your size, and you’re ready to move on to the second aspect of finding your perfect bra: your breast shape!

This is crucial because two women that are the same size (and that have measured themselves correctly) could require completely different bras based on their breast shape.

Many people — ladies included — like to think of breasts as coming in two shapes: small boobs and big boobs! This is honestly the number one mistake you can make when trying to find a properly-fitted bra. There are many, many different breast shapes. There are several types of small boobs, just like there are various forms of large boobs.

Figuring out what shape best describes your breasts usually comes with experience: after trying on bra after bra in various brands, you start to learn more and more about your shape and what works for you.

If you haven’t gone through the hassle of trying on hundreds of bras, you might find terms like “shallow breasts” and “root width” a bit daunting at first. I promise it’s not as complicated as it looks!

I’m going to guide you though the 4 main aspects of breast shape to the best of my ability while keeping it as simply as possible. And it’s going to be worth it. Knowing your breast shape is going to help you make better decisions and buy better bras.

Follow this guide, figure out your shape and your current fit issues, and you’ll be on your way to finding bras that fit you like a glove!


1. Projection: Do You Have Shallow Breasts?

Projection refers to the depth of your breasts. Projected breasts “project” to the front. The opposite of this is shallow breasts, which sit closer to the body and have less projection.

Typically, it’s those of us with shallow breasts that have more trouble finding a bra that fits well. This is because shallow breasts, having less projection, sit flatter on the body. Let’s say we have a projected boob and a shallow boob that have the exact same volume. What differentiates the two is how that volume is distributed throughout the breast. The shallow breast will have a lot more of its volume on the top part of the breast than a projected breast, and its distribution will be more even throughout the whole breast.

This leads to a common bra-fitting problem: the cup feels small on the top (breast tissue spills out on top) while feeling too big on the bottom (empty space because the volume of the breast is on top).

If you’ve noticed the problem above, chances are you have shallow breasts. Finding bras to better accommodate this breast shape can be more challenging, but you still have a lot of options.

2. Fullness: Are You Full On Top Or Full On Bottom?

Some boobs are fuller on the top half, some are fuller on the bottom half, and some are relatively even. Why does this matter? Because a lot of fit issues are related to fullness, and these issues affect both shallow and projected breasts.

If your breasts are fuller on top, you might find that a lot of bras cause spillage on top by digging into your breast tissue. If your breasts are fuller on the bottom, you might have noticed that your cups aren’t filled all the way up in some bras.

Nipple placement is the best way to determine whether you’re fuller on the top or on the bottom. Without a bra, lean over at a 90 degree angle. If your nipple sits in the front half of your breast, you’re fuller on the bottom. If your nipple sits on the back half, you’re fuller on top.

3. Root Width: Do Your Underwires Align With Your Breasts?

Understanding breast root is essential for basic aspect of a properly fitting bra: the underwire length. If you can determine if your breasts have a wide or narrow root, you’re going to quickly be able to tell whether or not the underwire of your bra works for you.

The root of a breast is its base. It’s where it’s attached to your torso — the picture below should make this concept clearer. A bra underwire mimics the natural root of the natural breast, and because not all breasts have the same breast curvature, it goes without saying that not all underwires fit all breasts. For a good fit, your underwires need to align with the natural root of your breasts.


The breasts on the left have a wide root and require a wider underwire. A bra with an underwire that’s too narrow will poke into the breasts and compromise fit. The breasts on the right have a narrow root and require a narrower underwire. An underwire that’s too wide will extend past the breast tissue and create discomfort.

Both of the breasts types above could be the exact same size in terms of band and cup! Root width is about the shape of the underwire only. This means that you could be wearing your ideal bra size and still experience underwire issues because the brand or model of bra you’re wearing isn’t accommodating to your specific breast width.

Breasts with a wide root have a lot of tissue closer to the sides of the torso and near the armpits. If your boobs tends to spill out of your bra near the armpits, you might have wide root breasts. This means that you should seek bras with underwires that are more extended than average.  Breasts with a narrow root, on the other hand, have the opposite problem: if you have narrow root breasts, the underwire of your bras might be too long for you, meaning that your boobs don’t fill all the cup space at the sides of your torso. Look for bras with shorter underwire to fix this issue.

To figure out if you have wide or narrow root, try on a few different bras and pay close attention to the outer sides of your bra, where the underwire ends. A properly-fitting underwire for your breast width should cup your breast exactly where it naturally sits. Does your underwire extend past your breast tissue?  Does your breast tissue extend farther than where the underwire ends?

4. Separation: Wide-Set Breasts VS. Touching Breasts

Another important factor that determines fit is the separation, or spacing, between your breasts. If there’s around 3 fingers between your boobs, they’re considered wide-set. If they’re very close together and touching, they’re close-set, or touching. This can be an additional problem when shopping for a good bra; if your boobs are wide-set or touching, pay close attention to the placement of your underwires and make sure they align with your breasts properly. Remember that the gore of the bra must lay flat on your body to ensure a proper fit.

  • Tip For Wide-Set Breasts: Look for demi-cup bras, where the gore is wider than average. Demi-cup bras are ideal for very separated breasts because the cups are more separated in themselves, matching the breasts.
  • Tip For Touching Breasts: Look for bras with smaller gores, with little to no separation between the cups, such as plunge bras. A plunge bra works great with touching breasts, especially if you’re looking for a bra that will emphasize your cleavage.

Like this post?

Check out my 27 Genius Boob Hacks Every Woman Should Know, below! I share my best tips whether you want to make your boobs look bigger or make them look better under any clothes. Sign up to the newsletter and get it for free!
27 Genius Boob Hacks Every Woman Should Know (Free Guide!)
Sign up below to get your free guide, plus exclusive content.

Our Popular Guides


  • Leave a Reply

    Your email address will not be published. Required fields are marked *