How Big Is a 34DD Bra Cup Size?

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In order for a bra to support and lift your bustline, the bra you choose needs to be the correct size and style for your breasts. Well-made bras can be expensive so make sure you know your bra size before you go to purchase a new bra. Think you might be a 34DD? In the article below, we discuss exactly how big a 34DD bra size really is.

How Big Is a 34DD?

If your bra size is 34DD, your under bust size is 33-34 inches and your bust size is 39 inches. A DD cup-size bra means that your breasts stick out 5 inches from your torso. The sister sizes for a 34DD bra size are 32DDD, and 36D.

If your bra size is 34DD, your underbust size is around 30-31 inches with a bust size ranging from 38-39 inches

Sister sizes refer to alternate sizes for your current bra size. To find your sister size, go up or down a band size and one letter smaller or larger than your current cup, simultaneously.

34DD Bra Size Details

34DD Bra SizeDetails
Underbust30-31 inches
Overbust38-39 inches
Size down32DDD(F)
Size up36D

Best Bra for 34DD Breast Size

Several bra types work best for DD breast sizes. A good bra for a DD size cup offers support without sacrificing comfort.

There are many options on the market for DD bras. They come in many different designs and styles, from balconette to wire-free bras. The most popular types of bra for DD are as follows:

For women with smaller sized frames with large breasts, like a 34DD, you need everyday support. My favorite? The Elomi Banded Underwire Stretch Lace Bra. It has really supportive bands and a nice, three section cup.

Difference Between 34D and 34DD Cup Sizes

The main difference between 34D and 34DD bra sizes is that with 34DD bra size your breasts are an inch larger than a 34D bra size. DD’s will project 5 inches from your chest, while D’s only go out 4 inches.

Breasts that are D cups can weigh about 3.06 pounds, meaning each breast may weigh 1.53 pounds. DD cups can weigh around 4.3 pounds  or 2.15 pounds per breast.

Graphic image that has 3 white dummies which corresponds to 32DDD/F, 34DD, and 36D as the sister sizes of a 34DD cup size

DD breasts need more support than D’s since they are larger and heavier. Most bras for women who have larger breasts have the following features to help keep their breasts well-supported:

  • Side panels with boning
  • Wider bra bands
  • Seamed cups
  • Wider padded shoulder straps to provide additional support and comfort

Related Questions

A dark blue wireless bra with a wide band and straps held by a woman

Is 34DD Medium or Large?

A 34DD bra is considered large among the standard sizes. It has a five-inch size difference between the bust and band.

Who Are Famous Personalities With a 34DD Bra Size?

Actress Kat Dennings, model Kate Upton, and wrestler Kelly Kelly are some of the famous personalities with a 34DD bra size. Singers Christina Aguilera and Jessica Simpson also wear 34DD bras.

Is DD Bigger Than D?

A DD cup is bigger than a D cup. You can try a DD cup if your breast tissue is spilling out of D cups.

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


A 34DD is a larger size compared to an A, B, or C.  To be comfortable wearing a 34DD bra, measure yourself and calculate your bra size. Confirm you are a 34DD and then find the best bra type for your body. Ensure that the bra cup accommodates all of your breast tissue, while still remaining comfortable.


Allena is the Founder and Editor of The Better Fit, a platform dedicated to empowering women with practical advice on bras and fitness, inspired by her own revelation of the widespread issue of incorrect bra sizing. Her expertise and tips have been recognized by major publications such as Cosmopolitan, Better Homes & Gardens, Insider, and NBC, making her a trusted voice in women's wellness and lifestyle.