Cup sizes explained: how bra sizes work
Are you unsure about your bra size or wondering exactly how cup sizes work? You're not alone. Many women unknowingly wear the wrong size, while a well-fitting bra makes all the difference in comfort, support, and appearance. On this page, we clearly explain how bra sizes are structured, how you calculate your size, and what cup sizes like C or D actually mean. This way, you can make the right choice with confidence.
What is a cup size and how does it work?
The cup size indicates the ratio between your bust measurement and your underbust measurement. It is therefore not a fixed size on its own. For example, a cup size C with a band size of 75 is smaller than a cup size C with a band size of 85. This sometimes makes the system confusing, which is exactly why it is important to understand the combination of band size and cup size.
The letter of the cup size is determined by the difference in centimeters between your bust measurement and your underbust measurement. The larger the difference, the higher the cup letter. This means that a larger cup does not automatically mean "large breasts," but is always proportional to your body.
How are bra sizes structured?
A bra size always consists of two parts: the band size and the cup size. The band size (e.g., 70, 75, 80) indicates the circumference of your body under your breasts. The cup size (A to M) indicates the difference between your bust and underbust measurements.
This combination ensures that bras fit your body precisely. That is why you might wear a 75D in one bra and find a 80C fits better in another situation. We call this a sister size, and this principle also helps you find a better fit if a bra just doesn't sit quite right.
How do you measure your bra size? (step by step)
Do you want to know what your bra size is? Then measuring yourself is the fastest way to get clarity. Use a measuring tape and follow these steps:
- Measure snugly around your underbust for your band size
- Measure loosely around the fullest part of your bust
- Calculate the difference between these two measurements
- Use the bra size chart to determine your cup size
Still in doubt after measuring? Then it helps to try on different sizes. After all, your body and personal preference also play a role in what ultimately feels most comfortable.
Cup sizes explained per letter (A to M)
Cup sizes range from AA to M. Each step up means a larger difference between the bust and the underbust. Below you will find an overview of our cup sizes in order:
cup AA, cup A, cup B, cup C, cup D, cup E, cup F, cup G, cup H, cup I, cup J, cup K, cup L and cup M.
By navigating directly to your cup size, you can immediately see which bras are suitable for your body. This makes choosing a lot easier and prevents bad buys.
What is a large cup size?
A "large cup size" usually starts from cup D or E, but this varies per band size. As explained earlier, a cup is always relative. For instance, a 70F is not the same as an 85F. Nevertheless, larger cup sizes often require more support.
That is why specially designed plus-size bras are important. These offer extra firmness, wider straps, and better weight distribution, helping you stay comfortable throughout the day.
Different types of bras for different cup sizes
Not every bra is suitable for every cup size. The right choice depends on your body and what you value: support, shape, or comfort.
For smaller cup sizes, light models like a triangle bra are often sufficient. If you are looking for extra volume, a push-up bra is a good option.
For larger cup sizes, support is essential. An underwire bra provides firmness and shape, while a non-wired bra can be very comfortable for daily use. A balconette bra is also popular due to its beautiful lift and fit.
Common mistakes when choosing a bra size
One of the biggest mistakes is wearing a band size that is too loose. This causes the bra to shift and you lose support. It is also common for cups to be too small, causing the bra to dig in or not fit properly.
In addition, many women rely on one fixed size, even though this can change due to weight, hormones, or age. Re-measuring regularly prevents you from unknowingly continuing to wear the wrong size.
Frequently asked questions about cup sizes and bra sizes
What does cup size C or D mean?
A cup size C or D indicates the difference between your bust and underbust measurements. The larger the difference, the higher the letter.
Is a larger cup always bigger?
No, a larger cup letter does not automatically mean larger breasts. The band size always plays a role in the total size.
Why does my bra size differ per brand?
Fits differ per brand and model. That is why your size may vary slightly, even if the size on the label is the same.
What is my bra size?
By measuring yourself and calculating the correct ratio, you arrive at your size. Always use a size chart as a reference for this.
How do I know if my bra fits well?
A well-fitting bra fits nicely, does not dig into the skin, and stays in place without creeping up. The band should carry most of the weight, not the straps.
Finding the right bra that really fits well
Now that you know how bra sizes and cup sizes work, choosing becomes a lot easier. It is not just about the right size, but also about the right model that suits your body and preferences.
Discover the complete range of bras or view all lingerie to find your perfect match. Choose comfort, support, and a fit that enhances your body. Once you wear the right bra, you will notice the difference immediately.