What Your Bra Size Really Means

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Bra Sizes Decoded

The truth about bra sizes

Have you ever wondered what the number and letter of your bra size really mean? You're not alone. It's a sizing method that has been in use for years and has gone through several changes. I started bra fitting in 2005, and have years of experience decoding bra sizes for thousands of happy clients.

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Band Size

What does a band size mean
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Your bra's band size is the number portion of your bra size. For example, in a bra size 32D, the 32 is the band size. 

In USA lingerie boutiques, department stores, and on bra shopping sites, band sizes typically range from 28 to 56. The vast majority of bra manufacturers in the USA create band sizes in the 32 to 42 range, with newer products emerging or brands creating more sizes to accommodate more women. USA band sizes come in even numbers, so you won't find one in a 33 or 45, for example. 

This number corresponds to the measurement underneath your bust, around your rib cage, in inches, not your actual bust measurement. It is not always an exact reflection of your actual underbust measurement. In the past, bra sizes were based on a pattern that used what's referred to as a "plus 4" method. This is now considered a "classical bra sizing" method. In this method, you add 3, 4, or 5 inches to the actual measurement of your underbust to get your bra band size. For example, if you measured 29 inches, you would wear a band size of 32 or 34. 

In recent years, in an effort to end the "plus 4" method, and as bra materials have more stretch, bra band sizes have an updated fit. In this newer method, you may add 0, 1, 2, or 3 inches to your actual measurement to get your desired band size. For example, if you measure 29 inches, you would try a 30 or 32 band size. Learn more about measuring yourself and finding your bra size

Every lingerie company sizes their undergarments and bras differently, as there is no agreed upon method or exact science, and trying on each bra and assessing its fit is the best method to find comfort and support. 

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Cup Size

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The cup size is the letter portion of your bra size. For example, in a bra size 32D, the D is the cup size. Once again, this is not an exact reflection of your actual bust measurement.

In the USA, bra cup sizes typically range from A cup to N cup. The further the letter is in the alphabet, the larger the cup size. In other words, an N cup is larger than an M cup, which is larger than an L cup, etc. 

In USA sizing, the sizes typically go like this from smallest to largest: 

AAA, AA, A, B, C, D, DD, DDD, G, H, I, J, K, L, M, N

DD is larger than a D cup. And DDD is larger still. It then jumps from DDD to G, because DD is thought to replace the letter E, and DDD is thought to replace the letter F. This is not true in all brands. Some follow a European method (not to be confused with the UK method, which I'll explain later in this article) of simply sizing A, B, C, D, E, F, G, H, etc. 

While the DD is larger than the D cup, this is not true for the A cup. The cup size AA is one size smaller than an A cup, and an AAA is even smaller. 

Keep in mind that every brand sizes their bras in a different manner, and finding the right size and fit relies on trying them on and determining what feels great and supports your bust - regardless of what the tag says. 

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How Cup Size Relates to Band Size

How to Measure Your Bra Size at Home

Did you know that a 32D is smaller in the cup and the band than a 34D? It's obvious that the 32 band is smaller than the 34 band because it's a smaller number, but what about the cup size? 

Typically, cup size is calculated by subtracting your band size from your bust measurement. Cup size is ​relative to the band size, meaning it changes as the band size changes. So, a D cup is not the same size or volume in each band size. As the band size gets larger, so does the cup volume, by one cup size. For example, a 32D is one cup size smaller than a 34D, two cup sizes smaller than a 36D, three cup sizes smaller than a 38D, etc. 

For that same reason, bra sizes have "sister sizes". These cup sizes may appear different, but the cup volume will actually be the same because the band size is different. For example, a 32D has the same cup volume as a 34C, or a 36B, or a 38A. The only difference is the band size (and possibly where the cups are positioned on the band). 

This can be confusing but very helpful to know, especially if you're adjusting your bra size to get a better fit. Let's say you are trying on a 34C bra, and the band feels a bit loose but the cup size seems ok. Instead of trying a 32C, you should try a 32D. That way, the cup volume will remain the same, and the band will be smaller. 

Because bra brands use different materials and fitting methods, this is one reason why you may have well fitting bras in more than one bra size in your drawer. I have several sizes! Once you get the hang of how a cup size relates to a band size, it will be much easier to get a better fit in your bra size. 

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Sizing in Different Countries

Bra fitting and design
Getty/Reza Estakhrian/Stone

You've heard me say that bra brands often size differently. I'm referring to how the actual bra will fit. Even in brands that use the same sizing method, like those each made in the USA, manufacturing practices, differing materials, and style differences mean each bra or brand may fit slightly different than the other. 

On the other hand, some brands actually use a completely different sizing notation than others, especially those in different countries. Here are a few popular bra sizing methods: 

European lingerie brands, use cup sizes that run A, B, C, D, E, F, G, etc. They do not favor the D to DD method. In addition, they use band sizes that run like 65, 70, 75, 80, 85, etc. Commonly, the 65 refers to a 30 band in the USA, a 70 to 32, 75 to 34, 80 to 36, 85 to 38 etc. So a USA 32DD would be a 70E. Examples of brands that use this method: Empriente, Prima Donna, and Marlies Dekkers

Although it's in Europe, brands made in France (and some other European nations like Spain) use band sizes that are similar but sized differently than others. Their sizing is 80, 85, 90 etc but is corresponds to US sizes in this way: 80 refers to a 30 band, 85 to 32, 90 to 34, 95 to 36 etc. An example of a brand that uses this method: Simone Perele.

Italian lingerie brands size their bras on a 1,2,3 method. The number refers to the band size. A 1 is a 32, 2 is 34, 3 is 36, etc. They also use an A, B, C, D, E, F, G etc. cup size method. So a USA 32DD would be a 1E. Example of a brand that uses this method: La Perla

In Australia and New Zealand, their band sizes run 8, 10, 12, 14 etc. An 8 refers to a USA 30, 10 to 32, 12 to 34, etc. Example of a brand that uses this method: Cake Maternity

In the United Kingdom, bra sizes are completely different, mainly because of the cup size. Their favored cup size method is A, B, C, D, DD, E, F, FF, G, GG, H, HH, J, JJ, K, KK etc. Notice that starting with D, they choose to use a "double" size for each letter. Alarmingly, it's also common to leave out the letter "i" and jump right from HH to J. Band sizes usually follow the US or European method, so a USA 32DD would still be a UK 32DD, and the E cup would be slightly larger in cup volume. Examples of brands that use this method: Panache, Tutti Rouge.

Some online lingerie retailers have made charts to help you choose your corresponding bra size from country to country. These charts vary on exactly which size matches up with another, especially when it comes to the UK and US sizes. Bra fitters in boutiques also disagree on exactly which size corresponds to which. Let's take the USA bra size of 32DDD. Most fitters and lingerie experts would agree that this translates to a European F cup. In the UK sizing, however, some would say that this corresponds to an E because it's the next cup size after 32DD. Others believe it would correspond to the UK 32F, and the E is a "half cup size" between DD and F. 

Some bras are sized with a basic size only and no cup size. For example Small, Medium, Large etc. or 1, 2, 3, etc. or 32, 34, 36 etc. As a rule of thumb, the cup size represented here is typically the corresponding B or C cup to that band size. Though, this is not always true. What is true, is that the bust volume of the bra will increase as the band or number size increases. 

Once again, trying on each bra and assessing its unique fit on your bust is key to getting the best bra size. This basic knowledge can help you to shop confidently, experiment with brands and sizing methods, and find what works best for you.