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Bra shopping can feel like solving a puzzle—band sizes, cup sizes, letters like A, B, C, or D… it’s no wonder many people get confused. If you’ve ever asked yourself, “What does ABCD bra size really mean?”, you’re not alone!
In this guide, we’ll break it down in the simplest way possible: what a cup size actually is, how it differs from bra size, what A, B, C, and D mean on a size chart, and how you can measure yourself to finally find your perfect fit.
What Is Cup Size?
A lot of people think the letter in a bra size only shows breast volume, but that’s not the whole story. Cup size is actually about the difference between your bust measurement and your underbust measurement.
Each inch of difference equals a cup size—so 1 inch is an A cup, 2 inches is a B cup, 3 inches is a C cup, and so on. It’s all about how your bust compares to your band size.
What’s the Difference Between Bra Size vs. Cup Size?
It’s super common to get confused between bra size and cup size. After all, they’re always written together—like 34B or 36C—so it feels like they’re the same thing. But in reality, cup size and bra size have different roles, and both are important in finding your perfect fit. Let’s break them down one by one:
1. Definition
Cup size represents the volume of your breasts, while bra size is the combination of your band size (the number) and your cup size (the letter). So, if cup size is one piece of the puzzle, bra size is the full picture.
2. Representation
Cup size is shown with letters like A, B, C, or D. Bra size, on the other hand, combines a number and a letter—like 32B, 34C, or 36D.
The number shows how tight or loose the band fits around your torso, while the letter tells you the cup’s depth or fullness.
3. Measurement Base
Cup size is measured by the difference between your bust and your underbust.
Bra size goes a step further by including both the band measurement and the bust difference. That’s why a 32B and a 36B aren’t the same fit—even though the cup letter is the same.
4. Function
Cup size focuses on how deep or voluminous the bra’s cups need to be. Bra size provides the complete fit, making sure the band holds snugly while the cups give the right amount of coverage and support.
Put simply, cup size is about the volume, but bra size is about overall comfort and shape. And when you’ve got your perfect size figured out, it’s time to find the bra that truly feels like you.
Explore Diana Intimates’ Everyday Essential T-Shirt Bra for smooth, all-day comfort, or the Invisible Breast Lift Bra for a natural lift and seamless look under any outfit!
What Does ABCD Bra Size Mean?
Sometimes, bra sizes can feel like a secret code — don’t worry, it’s not as complicated as it looks. Let’s break down what A, B, C, D, and the rest of the cup sizes actually stand for:
A. Band Size (the number part)
The number in your bra size (like 70, 75, 80, or in US sizing, 32, 34, 36, etc.) comes from your underbust measurement. This is the area right under your breasts, where the band of the bra sits.
For example, if your underbust measures around 73–77 cm, your band size would be 75 (or 34 in US sizing).
B. Cup Size (the letter part: A, B, C, D, etc.)
The letter doesn’t directly tell you how big your breasts are. In fact, it shows the difference between your bust (overbust) and underbust measurements. The bigger the difference, the bigger the cup letter. For example:
- A Cup = 10–12 cm difference
- B Cup = 13–14 cm difference
- C Cup = 15–17 cm difference
- D Cup = 18–19 cm difference
- E Cup = 20–22 cm difference
- F Cup = 23–24 cm difference
C. How It Comes Together
Your bra size is simply band size + cup size. For example, if your underbust is 75 cm and the difference between your bust and underbust is about 15 cm, your size would be 75C (or 34C in US sizing).
How to Measure and Find Your Cup Size
Finding your perfect bra size might sound tricky, but it’s actually pretty simple once you know how to measure your bra size. Getting the right size not only makes your bra more comfortable but also helps it look better under your clothes.
1. Measure the Band Size
Grab a soft tape measure and wrap it snugly around your ribcage, just under your bust. It shouldn’t be super tight—just comfortably fitted. This measurement is your band size.
For example, if your underbust measures around 32 inches, then your band size is 32. This number is what goes first in your bra size, like 32B or 34C.
2. Measure the Bust Size
Next, measure around the fullest part of your chest. Keep the tape level and relaxed (again, not too tight or loose!). Let’s say this measurement comes out to 36 inches.
3. Calculate the Cup Size
To find your cup size, simply subtract your band size from your bust measurement. The difference tells you the letter of your cup. For example, if your bust is 36 inches and your band is 32 inches, the difference is 4 inches, which corresponds to your cup letter.
Once you know your perfect fit, you can experience ultimate comfort with Diana Intimates’ Comfort 3D Push Up Underwire Bra With Modal Viscose Tea or keep it simple and versatile with their Everyday Essential Racerback Bra—both designed to give you support, style, and all-day ease.
Your Perfect Fit is Waiting!
Once you figure out what ABCD bra size means and how it matches your bust measurement, choosing the right bra becomes a whole lot easier. With the right fit, you’ll not only feel more comfortable, but also more confident in your everyday wear.
If you’re looking for a bra that feels like it was made just for you, Diana Intimates is the brand to trust. Their products are premium-quality but made so everyone can enjoy them. Every bra goes through a long, careful process with strict quality checks and attention to even the smallest details, so you know you’re getting something that truly fits and lasts.
With tools like their bra size calculator and bra sister size chart, finding your perfect fit has never been easier—because Diana Intimates believes that comfort, style, and quality should be for everyone!
FAQ
What is ABCD in bra size?
It’s the cup size, showing how full your bust is compared to your band.
Which cup size is bigger, B, C, or D?
D is the biggest, then C, then B.
