When shopping for the perfect bra, the terms bra sizing and bra fitting are often used interchangeably, but they refer to distinct processes that are crucial for achieving comfort and support. Understanding the difference between these concepts can transform your experience, ensuring you find a bras that feel great, flatter your shape and...actually fit.
Key Differences and Complementary Roles
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Focus: Bra sizing is about measurement to find a numerical size; bra fitting is about evaluation to ensure the bra suits your body and needs.
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Scope: Sizing is a starting point, ignoring shape or style; fitting refines the size with shape, brand, and comfort in mind.
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Process: Sizing uses physical measurements; fitting involves evaluating the match between bras's size, style, fit markers and your breasts' shape (projection, root width, root height, fullness, etc).
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Outcome: Sizing gives a size (e.g., 36G); fitting ensures the bra supports, flatters, and feels right.
What is Bra Sizing?
This is what everyone is hyper-focused on these days. It's not wrong, but it's only a starting point. Bra sizing is the process of determining your numerical and alphabetical bra size (e.g., 34C, 40F) based on body measurements. It’s a foundational step that provides a starting point for selecting bras, typically involving two key measurements: the band size (underbust) and the cup size (overbust measurement minus underbust).
How to Measure Bra Size at Home
- Posture: Stand or sit with your shoulders back in a good, solid, squared posture with your back straight. Hunching, slumping, or pushing your chest outward will skew the measurements and result in inaccurate sizing.
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Underbust / Band Size: Measure snugly around your ribcage, just under your breasts, using a soft tape measure. Tape be quite snug, level all the way around, and just below your breasts. If you need to check the back for level and placement, have your back to a mirror. If you fall in-between even numbers, round up to the nearest even number (i.e. measured 31" so round to 32"). This is your band size. The outdated +2/+4/+5 method (adding 4–5 inches) is common but less accurate, often leading to loose bands and too-small cups. Go with your underbust measurement as-is without adding anything (except rounding).
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Overbust: Measure around the fullest part of your bust (usually at nipple level). Ideally this is done wearing a well-fitted, unpadded bra, but since the purpose of measuring is to find a well-fitting bra, you can also measure this number without a bra (for best accuracy, go to "Tools" below). This should be just snug enough so the tape doesn't fall down. Don't smash your boobs on this measurement.
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Cup Size: Subtract the underbust measurement (i.e. 38 inches) from your overbust measurement (i.e. 42 inches). You will get a number that correlates to your cup size. Each inch corresponds to a cup size (1”=A, 2”=B, 3”=C, 4”=D, 5”=DD, etc.).In the examples, 42" minus 38" is 6" which is a DDD cup, so a 38DDD bra size.
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Tools: The A Bra That Fits calculator uses six measurements (loose, snug, tight underbust; standing, leaning, lying bust) for precision. No bra is worn for this measurement system.
- When to Use: Bra sizing is the first step before shopping, especially online or in stores with limited fitting services. It’s easy at home with a soft tape measure.
- Frequency: Re-measure once or twice a year or after life changes (i.e. pregnancy, weight fluctuations, menopause). It's also good to take a month and measure a few times throughout it to account for breast changes during your cycle.
What is Bra Fitting?
Bra fitting is the process of evaluating how a bra fits on your body, ensuring it provides comfort, support, and flattering shaping beyond the numerical size. It involves trying on bras, assessing fit markers (e.g., band snugness, cup coverage), and adjusting for shape, root width and height, style, and brand differences. This can be a daunting, frustrating and time-extensive task, but it's well-worth it in the end. Fitting refines the sizing process, tailoring it to your unique anatomy and preferences.
How Bra Fitting Works
- Shape Consideration: Fitting accounts for breast shape (e.g., full-on-top needs open cups, shallow breasts usually need wider cups). For example, Panache Jasmine suits projected, narrow-root breasts, while Wacoal Inner Sheen fits shallow, wide-root shapes.
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Style and Brand: Different styles (plunge, balconette, t-shirt) and brands (e.g., Freya’s stretchy bands vs. Panache’s firm cups) require fit adjustments even within the same size..
Bra Fitting tips for Beginners
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Fit Markers:
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Band: Should be snug, level, and not ride up. 80–90% of a bra's support comes from the band, so the band should be snug, but not to the point of constriction.
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Cups: Should encase and support your breast tissue without gapping or spillage.
- Underwire: Wires should sit in the inframammary fold (IMF), following the breast root all the way along its length. It shouldn't be out away from your breast tissue or cutting across it. This accounts for "root width" and there should be a match between it and your bra's underwire (or where it would be if it's wireless).
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Gore: The center piece between cups should tack flat against the sternum. Flat! Flat, flat, flat. If it's hovering off your skin out in space - your bra doesn't fit and you likely need a bigger cup size.
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Straps: Should stay in place without digging or slipping, providing minimal support. You should fit two fingers under it everywhere except at the top of your shoulder.
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Do the "scoop and swoop": Reach into the cups at the outer edges and lift and scoop your breasts upward and inward into the cups to ensure all the breast tissue is in the bra's cups.
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When to Use: Bra fitting is essential after determining your size, whether trying bras at home, in-store, or via online returns. It’s critical for finding styles that match your shape and lifestyle (e.g., sports bras for workouts, plunges for low necklines).
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Methods: Try bras in your calculated size and sister sizes (e.g., 32DD → 34D, 30E). Use online fit checks (or just email us!), posting measurements and photos for community feedback.
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Signs of Poor Fit: Riding bands, gapping/wrinkling cups, or digging wires indicate a need for adjustments, even if the size matches measurements.
Together, they form a two-step process: size first, fit second. Sizing provides the foundation, while fitting personalizes the experience, addressing the 70–85% misfit rate caused by poor sizing or shape mismatches.
How to Get a Perfectly Fitting Bra
Now that you have a solid fitting measurement and you've tried some bras on to assess fit, are you done? Well, maybe! If you landed on a bra in your size that fits well, you can call it a day. But if you're like most and you don't feel like you have the fit nailed, it's time to adjust.
Focus on the fit issues and adjust the sizing factors to correct. If you have cup issues, look at the cup size and go up or down. If the band is causing trouble, then adjust up or down as needed (also going down or up a cup size to maintain cup fit). You can read more about sister sizing in a previous blog post that will explain how to understand and purposefully change to a different band size.
The key is to never get hung up on one aspect alone. The secret isn't in sizing or fitting, it's always considering both and adjusting based on fit factors.
As always, if you have questions or need more guidance or information, you can reach us at billysbras@gmail.com or via the contact form on the website.
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