DD vs. DDD vs. E Cup Bra Size: What is the Difference?

When it comes to bra sizes, bra cup sizing can quickly become the most confusing component. Bra cup sizing is done using letters as opposed to the numbered system band sizing uses. When cup sizes are indicated using double, or even triple, letters, things can become confusing. Between DD vs. DDD vs. E Cup vs. F cup sizes, and regional bra sizing differences, this can all become confusing if you don't know what you're looking for.

Let's go through everything you need to know about calculating bra cup sizes and the differences between some of these common bra sizes.

The Math of Bra Cup Progression: 5, 6, and 7 Inches

Bra sizes are composed of two things: your bust measurement and band measurement. Different brands use different measuring systems, but at Glamorise, we determine bra size by taking the band measurement directly above the bust line and under the arms and the bust measurement around the fullest part of your bust.

The difference in inches between these two measurements indicates your bra size. If you have a 5-inch difference between these two measurements, you are a DD cup, 6 inches an F cup (or DDD) and 7 inches a G cup, and so on.

US vs. UK Cup Size Equivalency Table

The table below helps to clarify the confusion of bra cup sizes and regional differences between standard US and UK sizing.

Why Brands Use Different Letters for the Same Volume

Since there is no standardized bra sizing system used across the industry, different brands tend to use their own sizing systems. This means that a DDD cup in one brand may not exist in another. For example, some brands opt to use DDD to indicated 6-inch measurement difference, whereas Glamorise opts to use F cup. This is why it's imperative to follow an individual brand's sizing system and measuring guide to determine your bra size in their products.

In addition to differences between brands, there are usually differences in cup sizes between countries or regions. Whereas US brands prefer to use DDD or F to indicate a 6-inch difference, UK brands often use E to indicate the same.

3 Signs You Need to Move from a DD to an F Cup

If you usually wear a DD cup but are experiencing any of the fit issues listed below, this is likely a sign that you need to size up to a DDD or F cup bra.

• Breast Spillage: Also known as "quad-boobing," spillage happens when breast tissue spills out over the top or sides of the cups. In a well-fitting bra, the bra cups should always comfortably encapsulate your complete breast volume.

• Floating Gore: The center bridge of the bra should always lie flat against your chest. If it lifts away from your chest bone, this is a sign of an ill fitting bra.

• Painful Underwires: If you opt for an underwire bra, the wires should always rest directly under the breasts and touch the ribcage. If the underwires are resting on top the breast tissue instead and the bra band isn't hugging your chest, you likely are in the wrong bra size, which can also contribute to bra straps constantly slipping down .

Sister Sizing for DDD and F Cups

If you aren't familiar with sister sizing already, it's a great way to find a well-fitting bra. Some women find that sizing up in the band and down in the cup size, or vice versa, offers them a better bra fit. This is because cup volume is contingent on band size, meaning that it decreases or increases along with the band size indicated. For example, in Glamorise bras, a 38DD actually shares the same cup volume as a 36F. And a 40F shares the same cup volume as a 42DD.

If you are between band sizes, or prefer a more snug or loose band fit in certain bra styles, opting for your sister size is a great way to find a better fit.

Frequently Asked Sizing Questions

Is an E cup bigger than DD?

Yes, in UK bra sizing, an E cup is bigger than DD. An E cup is one cup size larger than a DD, indicating an extra inch of breast tissue across the fullest part of the bust.

What is an E cup in US sizing?

In US bra sizing, an E cup is most commonly labeled as a DDD or F. Both UK E-cup and a US DDD or F-cup sizes represent a 6-inch difference between the bust and band measurements.

About the Author

Maeve Gesualdi is a Fordham University alumna where she earned a Bachelor of Arts in Communications and Fashion Studies. Based in New York City, Maeve is part of the marketing team at Glamorise. Maeve regularly interacts with customers via social media and product reviews, as well as with influencers and models. She is constantly getting feedback on our products as well as gaining a better understanding of what women in our category struggle with and/or look for when searching for a bra. Aside from writing, she is passionate about all things travel and fashion.

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