Understanding bra sizing can feel tricky to the uninitiated, especially when you reach DD letters from a D rather than going straight to E. How does it all work and which is right for you? Simply put, the difference between a D cup and a DD cup is that; a D cup is larger than an A, B or C cup and slightly smaller than an E cup. On the other hand, a DD cup is slightly larger than an E cup, yet still smaller than an F cup.
The slightly trickier bit in measurements is that your size involves both a band and cup component, which must be considered together. Not all DD cups are the same. Cup sizes are relative and can differ between different brands. This is why it's important to measure yourself carefully before shopping for a bra. Many lingerie stores also offer professional fitting services so you can get the perfect size for your body type. Remember – Not all DD cups are the same.
Getting The Right Fit
Ever noticed how the fit of your bra band and underwire drastically changes as you move between sizes? Though cups are typically cut wider (though some deeper) when increasing size, there is a remarkable difference in both cup shape and bandwidth between brands. It's essential therefore to remember that not every D cup will fit the same, and not every DD cup will fit the same on your body.
We have a wide range of D and DD cup bras, click here to see our range.
Cup vs Band Sizes
Another critical bit about cup sizes is that they need two parts. They need both the ‘cup size’ and the band size to make sense. That "DD cup" doesn't exist on its own. The band size must be paired with it for comparison purposes, meaning a 30DD is both smaller than a 38DD in terms of the circumference measurement and also when looking at its capacity as well.
Band sizes can span from a petite 26 inches to an expansive 46 inches, while cup sizes range anywhere from the diminutive AA cup up to and beyond the generous J cup.
Bra size is calculated by taking both your chest circumference (measured around the rib cage just below your bust) and your breast volume into account. Generally, each inch increase in chest measurement equals a one-cup size increase.
Unsure of the right bra size for you? Take a look at our fitting guide which provides step-by-step instructions to help identify what defines a well-fitting bra and how to adjust it accordingly.
What is the difference between DD+ sizes and A-D sizes?
If the circumference of your ribcage is more than 5 inches larger than the size around the fullest part of your bust, a DD+ bra is likely to fit and offer you optimum comfort. With firmer underwires and extra pattern pieces in each cup for additional support, these bras are specifically made with sturdier fabrics and components that can accommodate fuller busts.
Why the difference between D & DD Bras matter
Recently, DD+ sizes have become much more prevalent. Various companies that manufacture bras in small cup sizes (A-D) now produce them for DD size and beyond too! Remember- every time your band increases, so does the decrease in cup size and vice versa, as illustrated in the table below.
| 28E |
30DD |
32D |
34C |
- |
- |
- |
| 28F |
30E |
32DD |
34D |
36C |
- |
- |
| 28FF |
30F |
32F |
34DD |
36D |
38C |
- |
| 28G |
30FF |
32FF |
34E |
36DD |
38D |
40C |
| 28GG |
30G |
32G |
34F |
36E |
38DD |
40D |
| 28H |
30GG |
32GG |
34FF |
36F |
38E |
40DD |
| - |
30H |
32H |
34G |
36FF |
38F |
40E |
| - |
- |
- |
34GG |
36G |
38FF |
40F |
| - |
- |
- |
34H |
36GG |
38G |
40FF |
We have a wide range of D and DD cup bras, click here to see our range.
Sizing Guide For D & DD Cups
Who should wear a D cup?
If you usually wear a C cup and your chest area is now overflowing out of the bra cups, you may want to look into sizing up - A D cup will fit more snugly than its DD counterpart.
Who should wear a DD cup?
If your breasts are larger than a D cup size and spilling out of the top or sides, you should consider opting for a DD cup instead. Similarly, if you're wearing an E cup and find that the cup doesn't sit smoothly against your breasts, then you might want to try a DD instead.
When to size down to a D cup
If you normally wear a DD bra but it now feels too big in the cups, you may need to switch down to a D cup if your band fits well but the cups feel too big. The cup of an appropriately-sized bra should encase all breast tissue without gaps in its shape. As 85-90% of the support from your bra comes from the band, this area needs to stay secure even when straps are taken off the shoulders.
When to size up to a D cup
Do you experience any discomfort or breast tissue spillage in your C or D cups? If so, we strongly advise that you size up to a DD cup. Always focus on how the bra actually fits instead of looking at its tag. Your size is just a suggestion rather than some fixed law - let yourself explore outside of your comfort zone and discover something new!
We have a wide range of D and DD cup bras, click here to see our range.
FAQS
Double D? Is that different to DD?
In case you've ever been in a store and heard the attendant refer to a "double D" bra size, that's what it is - simply saying two of the same letter instead of repeating them. For instance, double F means FF or GG for double G and so on.
Why is bra fitting so important?
When it comes to shopping for bras, size is literally just a number (and a letter). Whilst bra size gives you a basis to start from, it is important to keep in mind that every company follows a different sizing system and that each brand of bra will feel different when you try it on even if it's the same size as another one. This is why bra fitting is so important. Observing how a bra fits on the body is the best way to ensure you get the best and most supportive fit. You should pay attention to the straps, the band, the cups, and wires. Bands should be flat against the body and not ride up or be loose, straps should not dig in, cups should be filled but not overflowing.
Is D or DD cup bigger?
The cup sizes A, B, C and D are the core ones. As you move up through alphabetical order DD would be one size larger than D. This pattern continues until you reach double-letter (like FF) cups which also have a gap of one between them; for instance, E is bigger than DD just like how DD is greater compared to D.
Is the DD cup size big? Or small?
While it is true that a 38DD has more cup volume than a 30DD, it's critical to remember that this size is merely the beginning for many brands. This misconception of DD cups as "giant sizing" has been perpetuated due to the difficulty in obtaining larger sizes for an extended period of time.
These days, wearing a DD cup is quite popular, and many stores offer this size range. As bra cup sizing can go as high as L, LL or M, DD is by no means the biggest option available. What really matters in the end? Finding a style that fits you perfectly and provides you with all the comfort and support you need - not your size label!
We hope you now have a good overview of the difference between D and DD cup sizes, but for even more information check out our guide to 'how do bra sizes work'