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 D cup or a DD cup? D and DD cups 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 our article below, we discuss everything you need to now about D and DD cups.

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 a D cup vs DD cup:

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 D cups aren’t actually all that large – it is one of the most common bra size in the USA nowadays.

Having a D cup size bra means that your breasts protrude 4 inches out from from your ribcage. In more precise terms, a D Cup is when your bust measures 4 inches larger than your 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 cup size in the UK. In other countries, the D cup is still counted as a larger size rather than just average.

DD Cup 

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 cup and E cup are essentially the same size. Both DD cups and E cups have breasts that protrude 5 inches from the chest, which is 1 inch larger than a D cup.

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

Similarities and Differences

You might think that a D cup and DD cup 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 cups to help you distinguish between them:

Woman with a D cup size wearing a blue bralette
  • D and DD cups can have the same band length but different cup volumes. This slight difference 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 cups 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 Cup Bra Sizes

Cup Size Underbust Circumference Average Weight Best Bra Styles
D 4 inches 3.06 pounds Sports, t-shirt, plunge, longline
DD 5 inches 4.3 pounds Sports, wired, convertible, strappy

How Big Are D and DD Cups?

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

If you are a D cup, the average set of D cups weigh 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 cups weigh 4.3 pounds based on a 32DD bra size. This corresponds to the weight of a small chicken, which can be as heavy as 4 to 9 pounds.

D Cup and DD Cup Sister Sizes

Sister sizing is done when you or the bra fitter cannot find your exact bra size. Sister 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 cups:

  • 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 cup size is either going up or down. Sister sizing can either go left or right of the chart.

Related Questions

Are D and DD Cups Big Sizes?

In terms of normal bra sizes, D and DD cups 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 cups 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 cups look smaller. Celebrities like Tyra Banks and Emilia Clarke wear D-cup bras.

What Does a DD Cup Look Like?

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

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

Which Cup Size Is Better?

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


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.