Bra sizing systems
We will try to make sense of how different brands and regions address the sizing on their bra labels.
Traditionally, different countries/regions have been using a few standards on how to label their bras.
The most popular sizing systems around are US, UK, EU and what France and Spain uses. There is also an Italian system but is very not very common.
All these bra sizing systems agree in one thing, they all have a number to represent the band size and use letters to represent the cup size. The difference rely in the combination of rules they use for bands and cups.
Sizing by regions
UK sizing
Is starting to gain the most traction online for its apparent stability across brands and seemingly standard.
For its band sizes, it uses increments of two and all the bands are even numbers. Usually the smallest size is around 26 or 28 band. There is a rough correlation between this number and the perimeter of your ribcage in inches, this the increments are considered to be two inches bigger on each size.
For cups, the widely understood progression of cups goes as follows:
AAA, AA, A, B, C, D, DD, E, F, FF, G, GG, H, HH, J, JJ, K, KK, L, LL, etc..
As you can see it has a particular set of rules:
- Anything below A is smaller by adding more As to it, very unusual to find anything with more than 3 As together.
- After D comes double D, then single E and then F, then double F. There is no double E. This is pretty safe. I have not seen any brand that claims to use UK sizes and does double E cups.
- Beginning at F, all cups go single letter, then double letter although no letter I, don't ask me why.
- Since it is not a standard set on stone, it is unclear how it goes much further beyond KK cups. A few brands start to differ as of what goes next, but most people will expect the same single/double letter progression. Ewa Michalak for example has opted to skip O cups to avoid confusion.
US Sizing
This sizing, is what is most commonly found in retail stores in the USA. It is growing unpopular for its inconsistency across brands, and how quick it starts having differences making it very difficult to use to translate one size to another brand.
For bands, it uses the same rules as UK sizes, by roughly relating band sizes with inches and using even numbers on its progression. The translation to UK cups is direct, a 34 band is the same in both.
This system shows its weakness on the cups. Each brand that claims to use US sizing has implemented their own version of how cups should go, some of them go like this:
- AA, A, B, C, D, DD, DDD, E, F, G, H, I ...
- AA, A, B, C, D, DD/E, DDD/F, G, H, I ...
- AA, A, B, C, D, DD, E, F, G, H, I ...
- AA, A, B, C, D, E, F, G, H, I ...
As shown, things get pretty unclear on what happens after D or DD. Some brands show equivalences saying that DD and E are equivalent, others say that E is after DD. Some brands do DDD and others never label their bras like that. In some brands F cups are the 4th cup after D, in others it is the 3rd size after D.
US sizing, is usually known for its presence of DDD cups, no double cups (except DD) and I cups in brands that dare to reach as high. Most brands that claim to use US sizing rarely go beyond G cups. So it is impossible to translate a larger UK cup into "US sizing" since there is no standard and brands don't go as high, it is undefined.
EU Sizing
EU Sizing is growing increasingly popular due the rise of lingerie industry in Europe. Most european counries will use this and you will find a mix of UK and EU sizes on retail stores.
For bands, it uses odd numbers with increases of 5. Many brands that use EU sizing, will also add a US or UK equivalent on their tags, showing the conversion rules. An easy equivalence is that band 70 is equivalent to a UK or US band 32. From then on, every step of 5 on each direction translates to a increase of two on the UK/US equivalent.
Traditionally, EU brands have had more focus on smaller bands so it is possible to find bands as small as 50 (equivalent band 24 in UK/US). The conversion formula goes something like this:
- F(x) = (x / 5 + 2) * 2 <- Replace X with your EU band and will obtain the UK/US band
For cups, traditionally most brands have kept it simple by doing single letter progressions:
AA, A, B, C, D, E, F, G, H, I, J, K
Nevertheless, as with all of these systems, each manufacturer is free to implement whichever variation over this they think is a better idea. Some brands will skip H cups, others will add Ł as the Polish alphabet suggests, and skip Q cups once sizes get on that territory.
France/Spain sizing
This sizing seems more strongly used in Spain than in France lately. It is very similar to EU sizing in term of bands and cups with the difference that the cups have a 15 offset over the equivalent EU size. For example a EU 70 band would be size 85 on this system.
Give n the small number of brands using this sizing as their main labeling, there is no really a common rule on how the cups work.
Italy sizing
Very few brands will implement this scheme, namely a few Italian brands will. It is easily recognized because it uses numbers starting at 0.
These brands usually start at the equivalent US size 30, and in some cases they will start at the equivalent size 28 always starting at 0 so it is difficult to know what they exactly mean at that size. From then on they just go by normal numbers, 1, 2, 3, etc.
Cup wise, these brands traditionally focus on smaller range with a limited selection, usually ranging from A to D cups.
Index sizing
This is our home grown sizing system here at Bratabase to resolve ambiguity and to aid equivalence conversion between brands and sizing systems.
For bands it uses the US/UK standard since it is widely known.
Unlike all other systems, it uses numbers for cups, and it merely represents the number of cups starting at A. A size 34A would be a 34:1 index size, and increasingly so depending on each brand. We have configured most brands as we learn about their particular sizing system and implementation peculiarities in order to always provide a conversion to Index sizes.
You can read more about the rationale and caveats about index sizes here.
Other sizing systems out there
As hinted above, each brand is always free to implement their best idea of bra sizes regardless of what other brands do, here are a few examples:
- Sugar shape: One of the most radical changes, uses a combination of apparent EU bands and a number based with 2.5cm increases that represents the full bust measurement, separated by a slash / .
- Ampere: US based brand that uses what looks like a EU sizing system but their bands have a 2 offset over standard EU, so a size 65 in ampere is equivalent to a size 60 in EU or 28 in US.
- Lady Cameo: An old brand that has gone by other aliases, usually found in wholesale online retail that carries a very wide range of bands and cups. Uses US bands but a very strange single/double letter cup progression, showing cups such as BB, CC, EE, II, etc.
There is no real "UK/US/EU/etc" sizing
As explained above, you will see that all sizing schemes come with exceptions. Reality is that there is no global entity that dictates and regulates how each manufacturer should size their bras according to their region.
Each manufacturer has the liberty to use whichever bands or cup lettering system they please or they think it is right, or even worse, change their minds at any point in time.
What you will find is that there are some rules that certain brands follow and other don't, so any regional sizing system will never be 100% precise across all brands that claim to use it.
Changing sizing schema
Some brands will change their sizing in time after they have produced certain bras.
- True & Co - Added DD cup
- Parfait - Different conversions
- Panache - Using DDDDDD cups
- Freya - Changed US/UK conversions
- Alexis Smith - Added F/E cups