What Do the Numbers in a Bra Size Mean?

If you’re like most women, you’ve probably wondered at one point or another what the numbers in a bra size mean. Here’s a quick rundown of what you need to know.

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A bra size is composed of two elements: the chest size (also called the band size) and the cup size. The chest size is represented by a number (usually ranging from 30-44, with some companies offering sizes outside of this range), while the cup size is represented by a letter, with most companies using A-K as their sizing guide. It’s important to note that cup sizes are not consistent across all brands – a company may use one letter to represent a certain cup volume in one style of bra, but use a different letter to represent the same cup volume in another style. In addition, some companies may use the same letter to represent differentcup volumes in different styles (for example, two different styles of 32D bras from the same company may have slightly different cup sizes).

The best way to determine your true bra size is to be fitted by a professional at a local lingerie or department store. However, if you don’t have access to a professional fitter or if you prefer to do your own measuring, there are a few things you need to keep in mind. First, make sure you are wearing a non-padded bra that fits well – if your bra is too loose or too tight, your measurements will be inaccurate. Second, stand in front of a mirror and wrap a measuring tape around your chest, making sure the tape is level and perpendicular to the floor. Make a note of this measurement (in inches), rounding up to the nearest whole number if necessary. This is your chest size.

To determine your cup size, wrap the measuring tape around your chest again, this time positioning it so that it runs across the fullest part of your bust (usually at nipple level). Make another note of this measurement and then subtract your first measurement from it – i.e., if your second measurement was 33 inches and your first was 30 inches, 33-30=3. The difference between these two numbers corresponds to your cup size as follows:

1 inch = A Cup
2 inches = B Cup
3 inches = C Cup
4 inches = D Cup
5 inches = DD/E Cup
6 inches = DDD/F Cup
7 inches = G Cup etc…
Once you have determined both your band size and cup size, simply put them together (i.e., 32C) to get your true bra size.

The Band Size

The band size is the number part of your bra size. For example, in a 34B bra, “34” is the band size. The band size is determined by measuring around your chest, under your arms, and over the fullest part of your bust. To get this measurement, you will need a soft tape measure.

The band size goes up in even numbers. For example, 34, 36, 38, 40, 42… etc. Theoretically, it should be easy to find your band size by trying on different sizes and seeing which one feels most comfortable. However, this isn’t always the case. Many women find that they are one band size in one brand and a different band size in another brand. This is because there is no industry standard for sizing bras and each company has their own way of sizing their products.

If you are having trouble finding your band size, don’t worry! There are a few things you can do to try to determine your size. First, you can try using a conversion chart. These charts take into account the different sizing methods used by different brands and can help you find your approximate size. Additionally, you can try going up or down a band size until you find one that feels comfortable. Remember, the band should be snug but not too tight. It should lie flat against your skin and should not ride up in the back.

once you have found a comfortable band size, you can move on to finding your cup size…

The Cup Size

In order to determine your cup size, you need to measure the circumference of your chest at its fullest point and the circumference of your bust at its fullest point. Once you have both of those measurements, you subtract the chest measurement from the bust measurement. The difference between the two will correspond to a letter in the alphabet. If there is no difference between your chest and bust measurements, then your cup size is considered to be an “AA”. The cup sizes progress through the alphabet as follows:

AA = no difference
A = 1 inch
B = 2 inches
C = 3 inches
D = 4 inches
DD/E = 5 inches
F = 6 inches
G = 7 inches

So, if your chest measured 33 inches and your bust measured 35 inches, then the difference would be 2 inches. That means your cup size would be a “B”.


A woman’s bra size is determined by two factors: the band size and the cup size. The band size is the number part of the size, and it indicates the measurement around your chest, just under your arms. The cup size is the letter part of the size, and it indicates the measurement of your bust at its fullest point.