C Cup vs B Cup Bra Sizes In Review

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For the longest time, C and B cup sizes were believed to be the standard cup size in the US since cup sizes were invented. This standardization makes it difficult for people to differentiate between C cup vs B cup. In this post, we’ll discuss these two sizes in depth.  

C Cup vs B Cup General Overview 

The first bra sizes were small, medium, and large which soon evolved to sizes A-C. Technology has made the underwear department experience a lot of changes since cup-size bras first entered the market.

A woman wearing an almond beige color bra posing

C Cup Size

C’s are normally a small-to-medium cup size unless the person is underweight or slim. It entails a three-inch difference between the bust of your breast and the ribcage.

B Cup Size

B cup size, when measured, is when a woman’s breasts are two inches apart from her chest. This is the second smallest after A cup size.

C Cup vs B Cup Similarities and Differences

Before looking at the similarities, differences, and major distinguishing factors of the two sizes, let’s look at what makes one have either a C cup or B cup size. A-C cup or B cup breast size may vary depending on:

  • Genetics: If a mother has small breasts, the girl is likely to have the same and vice versa. It is hereditary.
  • Weight: Fat and weight is important in terms of density and breast tissue which affects the cup size you wear.
  • Exercise: The pectoral muscles a woman builds during exercise increases the breast tissue. Even though it hardly affects your breast size, it can make them look perkier.
  • Breastfeeding and pregnancy: A hormonal change in pregnant women causes them to have more collagen fibers that help give their mammary glands volume.

Comparing C Cup and B Cup Bra Sizes

Cup Size Underbust Circumference Average Weight Best Bra Styles
C 3 inches 1.52 pounds Wired, wireless, push-up, seamless
B 2 inches 1.01 pounds Wireless, bralette, t-shirt


C cup size and  B cup size are considered to be the average size for most women.  This is because they fall in the middle of the range from A -G.

A woman wearing an almond beige color bra sitting


The major distinction in bra cup sizes is depicted from the shape of a woman’s breasts rather than its actual size. So what distinct features differentiate the C cup from the B cup?


If we are using a fruit analogy, the C cup resembles a grapefruit and the B cup is an orange. C and B cups look different from one person to another depending on both your ribcage and bust measurement. B cup size is just next to A cup size, hence slightly bigger.

Women sometimes wish to have larger breasts so you will find them trying to wear C cup-sized bras and the reverse is true. This should never be the case. It is important for every woman to accurately measure their cup size using a tape measure at home or if not able, get assistance in a bra or lingerie store.

Bust sizes

Considering that most brands range from A (Smallest) to the letter F (Largest), the C cup is considered average. It features three inches to the underbust circumference. The B cup is actually two inches in the measurement of its band size. The cup volume differs based on the bra‘s unique size.

Breast size fluctuates and it has a slot to do with a woman’s menstrual cycle. You could either move one size higher or lower size your bra up or down. Sizing up means going one bra band rank higher and a letter lower while sizing down means lowering the band size and going a letter up in rank in your bust.


Cup sizes may differ depending on how many breast tissues a woman has. However, the average B cup size approximately weighs 1.01 lbs. To paint a clear picture, this is equal to 15 small pancakes.

The C cup size is roughly 1.52 lbs. At this weight, this is the equivalent of one newborn polar bear cub. It can also be compared to 25 small pancakes.

Breast Augmentation

Breast augmentation in simple terms can be defined as a form of breast enhancement. It can also be called augmentation mammoplasty. The procedure entails putting implants below the breast tissue.

The question of whether a C or B cupped size should undergo a breast augmentation depends on a doctor’s guidance. Generally speaking, you should never go for more than two size cup differences. A-C cup would be ideal for women who have a natural A or B cup.

Breast implants require adequate support from your bras, and you’ll need to update your wardrobe with the correct size.

Major Distinguishing Factor 

The major difference between a C and B cup is the amount of space it occupies in terms of inches. A C-sized bra puts you at 3 inches above your rib cage.

A woman wearing an almond beige color bra posing side view

This means that only half as much breast tissue will be covered by fabric on each side (although some lingerie may come with extender straps). While in a B-sized cup the result is a 2 inches difference from your ribcage to the bigger area of your breasts.

When to Use a C Cup Size Bra

You can use a C cup size bra when wearing the following bra types: 

  • Wireless Bra: It is supportive even though it’s wireless. It rests flat and smooth against the body, so it’s perfect for fitting clothes.
  • Push Up Bra: It has a sexy design, a high stretchy band that can turn into strapless.
  • Seamless Bra: Provides comfort thanks to the lightweight, breathable and flexible fabric.
  • Seamless Underwire Bra: It’s best for wearing almost any type of top as it won’t give you visible bra lines and provides full coverage. It has strong support which is comfortable padding that enhances boobs.

When to Use a B Cup Size Bra

A B cup bra is a great choice when wearing a:

  • Wire free bra: This is a good bra to wear if you stretch and move a lot. It has removable pads so you can wear them under your day-to-day outfits.
  • Lace bra: While it does have an underwire, it’s optimized to curve and give a comfortable position so it never hurts.

Related Questions

Are B and C Cups Good Sizes?

Like any other sizes, B and C cups are good sizes. While they are generally considered small, keep in mind that the breast volume varies per person. You can highlight or increase the appearance of your bust as long as you wear the right bra.

What Does a B Cup Look Like?

A B cup is quite small in comparison to other sizes, with an overbust circumference of just two inches. Celebrities with B cups include Jessica Alba, Rihanna, and Miranda Kerr.

What Does a C Cup Look Like?

In comparison to other cups, the C cup appears smaller as well. Consider famous people like Salma Hayek, Emily Ratajkowski, and Cara Delevingne.


B cup-sized women and C cup-sized women are beautiful. In fact, all bra sizes are! As long as you pick the best bras to flatter your silhouette, your boobs will look fantastic whether they are big or small.


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.