D Cup vs DD Cup Bra Sizes In Review

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Which bra size is bigger, D cup or DD cup? How can find out if you are a D cup or a DD cup? D and DD are close in size, but they are not the same. If you are wondering what the difference is between a D cup and a DD cup, you have come to the right place. In my article below, I discuss everything you need to know about D and DD.

D Cup vs DD Cup General Overview

In 1937, the concept of bra sizing was introduced in the United States. Soon after, in 1948, bra sizing made an appearance in the United Kingdom. Bra sizing originally started with only A, B, C, and D cups. For a long time, all bigger bra cup sizes were just known as D cups.

Graphic image that features a drawing of two figures wearing a red bra, which compares a D cup bra size against a DD cup bra size

Let’s take a look at the general overview of these cup sizes:

D Cup

A D cup is the fourth cup size on the bra size chart, coming after A, B, and C cup sizes. The D cup is commonly considered the first “big size” on the chart, though recent surveys show that Ds aren’t actually all that large – it is one of the most common bra sizes in the USA nowadays.

Having a D cup means that your breasts protrude 4 inches out from your ribcage. In more precise terms, a D Cup is when your bust measures 4 inches larger than your bra band size.

Woman with a DD cup size wearing a black bra

The D cup has many variations when it comes to band sizes. The common D cup band sizes are from 32D up to 44D. A 36D is the most common or average size in the UK. In other countries, the D cup is still counted as a larger size rather than just average.


In the 1950s, after different famous brands in the US recognized the DD cup, the UK followed through with the name E. Confusing, right? The DD and E cup are essentially the same size. Both DD and E bra cups have breasts that protrude 5 inches from the chest, which is 1 inch larger than a D cup.

The DD is definitely a larger size, though the DD is arguably the average size in the US

Similarities and Differences

You might think that a D cup and a DD are the same because of their name or because there’s only an inch difference between them.

Here are some of the similarities and differences between D and DD bra cups to help you distinguish between them:

Woman with a D cup size wearing a blue bralette
  • D and DD can have the same band size but different bra cup volume. This slight difference in cup volume can affect the way your bra fits and supports you. For example, you can see in the size that there are 34D and 34DD. It means that they have the same band length, perhaps because of your body shape. 
  • If you are a 34D and you wear a 34DD, you will feel the difference when it comes to the cups. The cup volume will be much bigger, and you will not fill them fully.
  • Both of these sizes need more support, especially on the under band because if you are a D or DD cup, your breasts are heavier. 
  • Unsupportive and uncomfortable bras may cause pain and discomfort, especially if you wear them all day. Proper lift is also necessary to prevent sagging.

Comparing D Cup and DD Bra Sizes

Cup Size Underbust Circumference Average Weight Best Bra Styles
D 4 inches3.06 poundsSports, t-shirt, plunge, longline
DD 5 inches4.3 poundsSports, wired, convertible, strappy

How Big Are D and DD?

To help you imagine how big D and DD are, imagine this:

If you are a D cup, the average set of D weighs 3.06 pounds. Your breasts are the weight of a small rabbit, which can weigh from 3 to 5 pounds. On the other hand, the average DD weigh 4.3 pounds based on a 32DD size. This corresponds to the weight of a small chicken, which can be as heavy as 4 to 9 pounds.

D Cup and DD Sister Sizes

Sister sizing is done when you or the bra fitter cannot find your exact size or cup volume. Sister bra cup sizing is a more recommended method of getting a good fit rather than going up or down a cup.

Woman wearing a red bra sitting on bed

The incorrect size of the cup can cause too many problems. For instance, a smaller cup cannot accommodate all of your breast tissues, resulting in side spillage under your arms and your breasts overflowing the top of the cups.

The wrong band length can also cause back fat bulges and insufficient support. The bra will also slide up with your every movement causing your breasts to escape the cups at the bottom.

If the cup is too big, you may see some wrinkles under your shirt. Sometimes, when you move, the loose cups will be very obvious. A big-size bra can also result in too much bouncing, causing the breasts to sag.

Here are some examples of the sister sizes of D and DD :

  • If you are a 28D cup, your sister sizes are 26DD, 30C, 32B, 34A, and 36AA.
  • If you are a 28DD, your sister sizes are 30D, 32C, 34B, 36A, and 38AA.

As you may have noticed, most of the sister sizes are just an increasing number on the band length by two inches, and the size is either going up or down. Sister sizing can either go left or right on the chart.

Related Questions

Are D and DD Big Sizes?

In terms of normal bra sizes, D and DD are regarded as large. The bra you’re wearing, and the band size still affect how you will actually look.

What Does a D Cup Look Like?

Some D may appear smaller, while others may look larger. For instance, a tiny body frame may make a D cup look quite large, while a bigger ribcage will make D look smaller. Celebrities like Tyra Banks and Emilia Clarke wear D-cup bras.

Is The DD Cup Size Big?

Due to the five-inch gap between the band and bust, DD cups appear a little bigger than D . Halle Berry and Kat Dennings are all rumored to have DD.

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

Which Size Is Better?

D and DD cups are both considered average sizes though you may sometimes have difficulty finding a well-fitting bra for your body. No matter what, always take your measurements before you go bra shopping. Only consider sister sizing if your exact size is not available.


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.