How Big Do Bra Cup Sizes Go?

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Wondering about how big bra sizes go? Many women are curious about this as it’s not easy to find larger sizes in stores. We discuss the bra size range available in my article below.

How Big Do Bra Sizes Go?

Bra band size range from a 28 to a 56, though the larger sizes are mainly found online or in specialty stores.  With most U.S. brands, bra cup sizes range from A being the smallest size to H being the largest available, though there are larger cup sizes in existence. Currently, the biggest bra size known is a 102 ZZZ, which was a custom designed bra.

Graphic image that has images depicting how big, large and XL bra sizes can differ from each other

If your bra size is bigger, you may have to shop in a specialty store like Lane Bryant, Torrid, or Avenue; or have a custom-made one created for you. This can be expensive, but it is essential to ensure that you have a bra that fits you well and is comfortable to wear.

What Determines Bra Size?

A woman’s bra size is determined by her band size and cup size, expressed as numbers and letters. The difference between your torso measurement and bust measurement determines your cup size.

Bigger Breast Cup Sizes

Most women’s cup sizes are either A, B, or C.  D cups are larger, and are considered above average in size.

Only 1% of women have boobs larger than a D, and DD (known as E with some brands) and DDD (known as F with some brands) are even larger cup sizes and even less common. Cup sizes E, F, G, H are available online and in stores. As so few women have these cup sizes, they can be hard to find.

A woman smiling widely wearing a pink high-neck bralette and sliver earrings and is looking down at the window

Let’s look at the I, J, and K cup sizes in depth.

  • I cup size: For this cup size, the bust measurement is 9 inches bigger than the torso measurement.
  • J cup size: For this cup size, the bust measurement is 10 inches bigger than the torso measurement.
  • K cup size: For this cup size, the bust measurement is 11 inches bigger than the torso measurement.

Comparing Bra Sizes

Size Description Cups
Big 5 to 9-inch difference between the band and bustA, B, C, D, E, F, G, H
Large 10 to 12-inch difference between the band and bustI, J, K, L
Extra Large More than a 12-inch difference between the band and bustM to ZZZ

What Is a Big Bra Size?

For a bra size to be considered “big”, there has to be a five to nine-inch difference between the band and bust measurements. Cups DD/E, DDD/F, G, and H fall in the big bra size category and are outside the standard cup sizes of A to D.

What Is a Large Bra Size?

For a bra size to be considered “large” there has to be a ten to twelve-inch difference between the band and bust measurements.

Ladies who have large breasts use I, J, K, and even L cup sizes, which are considered large cups in the bra size range.

What Is an XL in Bra Size?

An XL in bra size will have a bust and band size difference of more than 12 inches. Women with XL breasts would be wearing the cup sizes ranging from M to ZZZ.

Woman in a pink full-coverage bra and blue denim pants is seated on a white bedsheet in the bedroom

What Makes Breasts Bigger?

In most cases, bigger busts are caused by genetics. If bigger breasts run in your family, there is a good chance that you will also have bigger breasts.

Your breasts may also become bigger due to medication, weight gain, menopause or hormone issues, thyroid conditions, and pregnancy/breastfeeding.

Pros and Cons of Larger Breast Sizes

Bigger breasts can be both a blessing and curse. American culture tends to find big breasts attractive and desirable. Bigger breasts can bring a woman unwanted attention and can cause back, shoulder and neck issues due to the weight of the breasts.

Related Questions

What Is the Biggest Bra Cup Size?

Although rare, ZZZ is currently the biggest cup size. Annie Hawkins-Turner has a ZZZ cup size that weighs 89 pounds.

How Will I Know My Cup Size?

You must calculate the size difference between the band and the bust to find your cup size. For instance, you have a C cup if there’s a three-inch difference between your underbust and overbust.

How Big Will My Bra Size Be?

The final size of the breasts may depend on the full development once you reach 18 years old. However, your breasts may continue to enlarge during adulthood, depending on your diet, medical condition, and lifestyle.

Bra Size Measurement & Cup Size | A, B, C, D, DD Bra Sizes AND Extra Large Breasts


Embrace your breast size. Flaunt what you got. There are bra options available, no matter how small or how big your breasts may be.


Hi there, I’m Allena, Founder and Editor of The Better Fit. I’ve always had a passion for finding ways to help women improve various areas of their lives. I have researched and worked to create this website so women would have a place to come and be informed about an article of clothing they literally wear every day.