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The Difference Between an F & DDD E Bra Cup Size

The Difference Between an F & DDD E Bra Cup Size

Bra, which is shorthand for brassiere, is an undergarment meant to cover the breasts and provide support to the wearer. It is considered one of the most complicated garments ever made. 

You may be wondering why bras come in so many sizes. This is because you need to consider your breast shape, cut, cup size, and even your torso when selecting a bra. Bra sizes are not the same as other clothing. Sometimes a brand’s cup or band size may be different. There are bra sister sizes you can use to ensure the perfect fit.

A DD is a breast measurement that is 5 inches larger than the size of the band. A DDD is a breast measurement that is 6 inches larger than this band size. European brands may have F and E cups.

Keep reading to know more.

What are the components of a bra?

A bra is made up of:

  • Chest band
  • Cups
  • Hook and eye
  • Underwire
  • Shoulder Straps

Chest Band 

Your brassiere’s chest band serves to secure or hold your undergarment during wear. It should be snugly fitted as it carries the bulk of your breast weight. It is therefore an important consideration when sizing bras. It has two parts.

  • Wings – These are usually attached to your bra at the cups, while the band’s ends are typically located at its ends.
  • Center Gore – This refers to the space between your bra’s cups. The shape and size of the cups can be affected by the height and size of the gore. The gore can either be a source or a barrier to bra wearers.


These cups can be either round or pointed-shaped. The cups, just like the chest band are important in bra size. Because they can be customized to meet the individual needs of each woman, they come in a variety of sizes and styles.

Apex: This is where the shoulder straps attach to the front and the highest point in the brassiere’s cups.

Hook and Eye 

Except for sports bras that are not equipped with a closure mechanism, most bras have one. Bras are typically designed with hook and eye closures. Women can adjust the bra’s band to ensure a secure and comfortable fit.

Underwire. Although not all bras have underwires, most bras do.

Shoulder Straps  

These straps can stretch over time. They are therefore equipped with adjustable sliders that allow for tightening.

What are bra sister sizes?

A bunch of bras hanging

Bra sister sizes are bra size groups that have identical cups or volumes but differ in the length of the bands. A size 34B, for example, is the same size as a 32C or 36A. It is a measurement of your waist and inseam. A 28-inch waist may fit you well in jeans. However, depending on your height, you might prefer a shorter or longer inseam.

We will break it down.

The size of the bra size, or how much breast tissue it can hold, will affect the volume. To maintain the amount of breast tissue that the cup can hold, the sister size must be reduced as the band grows in width. If you are a 34C and feel great in your cup, but your band is a little tight, you can go up to a 36B.

You can adjust your bra size to fit your unique body by using the ratio of bra sizes.

It can be extremely helpful to know the size of your sister before you shop. Even better, you won’t have to measure your bra as often and will find a bra that suits your unique shape much easier.

However, accurate measurements are key to getting the perfect fit. Your breast shape can also affect how certain bras fit. This is where sister sizes come into play. You can quickly determine which size will work best for you. It doesn’t matter what size bra you choose, as long as it is comfortable with maximum support. This is the most important benefit of knowing your sister’s size.

It can be difficult to find the right size bra for you, especially since bra sizes are not uniform. Bra sizes can vary from one style to another and even from one brand to the other. It is also important to know the size system of a particular brand’s lingerie – whether they use US, UK, or EU bra sizes.

How do you fit bras?

When fitting bras, there are two important measurements: (1) the size of the band and (2) the size of the cup. Your bra size is determined by the circumference and area under your breasts. The United States uses inches for band sizes. Their numerical labels, such as 30, 32, 34, etc., are used to indicate their numerical values. are usually equivalent to the underbust circumferences of women, rounded to the nearest even number.

Your cup size is determined by your breast size or bust. This is done by subtracting your underbust circumference from your chest circumference. The chest circumference is measured at the top of your highest breasts. It is often recorded in inches according to U.S. sizing standards. 

Once you have determined the difference between your underbust and bust, the answer can be converted to the alphabetical letter that corresponds (e.g. A, B C, D etc.). The U.S. cup sizes chart.

If your bust measures 34 inches and your underbust 32 inches, the difference is 2 inches. This is the alphabetical equivalent in a U.S. cup sizes chart. It’s called B. Your recommended bra size is 32B, which is the band size plus cup size.

Have a quick look at this video to know more:

Are DDD and F the same thing?

Although it might sound confusing, a DDD can be the same size as an F. Sometimes they are labeled differently depending on the brand. 

You can go up to size D, which is the equivalent of size E, or size DDD, which is equivalent to size F, or size DDDD, which is equivalent to size G.

Have a look at this table for reference:

US Cup SizeThe Difference between Bust Size and Band Size
Inches (in. )Centimeters (cm. )

What is the difference between bra sizes F and E?

To simplify, in the standard U.S. size, there are no F or E cups. A DD is a breast measurement that is 5 inches larger than the size of the band. A DDD is a breast measurement that is 6 inches larger than this band size. 

European brands may have F and E cups. There are also differences in the sizes of brands.

Cup sizes are the same in Europe/France and the U.S. A cup (U.S.) equals an “A” cup in Europe/France. B=B, C=C, and other exceptions are made for “DD” or “DDD” cups. 

Many European brands, as well as some American brands, use the lettering E for a DD size cup and F for a DDD size cup. You can use the cup size guide to help you decide which size cup is right for you.

What size is an F-cup?

This chart will help you determine your cup size.

(United States)
(United Kingdom)
1/2 “AAAA

A DD cup is larger than a G cup. This is because there is no uniformity in cup sizing. You might be a G cup with one brand, but an F with another.

Final Thoughts

A girl standing

Have your bras professionally fitted. Shop at a clothing or bridal shop that has a wide selection of sizes and styles. Hire professional bra fitters. These trained fitters are familiar with other factors that can affect the selection of the right bra for you, such as your cup size and band size.

Before you shop, measure yourself. Your body measurements should be checked every six months. Breast size and shape can change due to factors such as weight gain or pregnancy. Follow the above instructions to determine your bra size. This will make it easier to try on bras.

When trying out brassieres, wear a thin T-shirt. When you wear sheer or thin clothing, your bra should look like this. It’s possible to not want your bra to be too obvious, so you need to know what the bra looks like when you wear sheer or thin clothing.

Make sure you are wearing the correct bras. You can test whether a bra fits well by placing your breasts forward at 45 degrees. Next, adjust the shoulder straps to ensure that your breast tissue is supported and covered. To determine if your bra size is correct or incorrect, look out for the red flags.

Don’t let your bra size affect you emotionally. You want a bra that fits well and offers you comfort and support. You don’t have to be embarrassed if you have a larger or smaller cup. The bra size labels are just for your convenience. They don’t define you.

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A web story discussing the differences can be found when you click here.