What Your Bra Size Really Means

woman measured her breast with a measuring tape
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Bra Sizes Decoded

The truth about bra sizes

If you've 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. This is the single most important tool for bra fitters. It's reported that more than half of American women are wearing the wrong size bra. If you think that might include you, the best thing to do is to go to a reputable store and get a fitting. Your body changes over time even if you don't gain or lose weight, and getting a professional fitting is the best way to find out your size and get a bra that is the most flattering to you. And that's the whole point of this garment. Every lingerie company sizes their undergarments and bras differently because 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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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 American 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 United States create band sizes in the 32 to 42 range, with newer products emerging or brands creating more sizes to accommodate more women. U.S. 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. This is 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 four" method. This is now considered a "classical bra sizing" method. In this method, you add three, four, or five 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 four" method, and as bra materials have more stretch, bra band sizes have an updated fit. In this newer method, you may add zero, one, two, or three 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

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Cup Size

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 U.S, 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, and so on.

In U.S 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) of simply sizing A, B, C, D, E, F, G, H, and so on.

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. 

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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 both 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, and so on through all the band sizes. The cup size means nothing without knowing the band size.

For that same reason, bra sizes have "sister sizes." These cup sizes may appear to be 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, you could have good-fitting bras in more than one bra size in your drawer. 

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Sizing in Different Countries

Bra fitting and design
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Even in brands that use the same sizing method, like those made in the U.S., manufacturing practices, differing materials, and style differences mean each bra or brand might fit slightly different than another.

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, and so on. They do not favor the D to DD method. In addition, they use band sizes that run like 65, 70, 75, 80, 85, and so on. Commonly, the 65 refers to a 30 band in the U.S., a 70 to 32, 75 to 34, 80 to 36, 85 to 38. So a 32DD in U.S. sizing would be a 70E. Examples of brands that use this method: Empriente, Prima Donna, and Marlies Dekkers. 

Brands made in France and Spain use band sizes that are similar but sized differently than others. Their sizing is 80, 85, 90, and so on, but it corresponds to U.S. sizes in this way: 80 refers to a 30 band, 85 to 32, 90 to 34, 95 to 36, and so on through the sizes. 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, and so on. They also use an A, B, C, D, E, F, G cup-size method. So a 32DD in U.S. sizing would be a 1E in Italy. Example of a brand that uses this method: La Perla. 

In Australia and New Zealand, their band sizes run 8, 10, 12, 14, and so on. An 8 refers to an American 30, 10 to 32, 12 to 34, and so on through the band sizes. 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. The U.K.'s favored cup size method is A, B, C, D, DD, E, F, FF, G, GG, H, HH, J, JJ, K, KK, and so on. Notice that starting with D, they choose to use a "double" size for each letter. Band sizes usually follow the U.S. or European method, so a 32DD in the U.S. would still be a U.K. 32DD, but the E cup would be slightly larger in cup volume. Examples of brands that use this method: ​Panache, Tutti Rouge.