I've been working this weekend on adding proper support for multiple sizing systems on the site. So far it's shaping up nicely, but I can't help to get surprised on how different all charts are.
The example on the left is the tag of a 30G Jeanie by Parfait and you can see all the listed sizes:
- UK: 30G
- USA: 30I
- Japan: J65
- Italy: 0G
- France: 80I
- Europe: 65J
- Australia: 8GG
- Int/China: 65I
That's almost the combinatorial of [30, 0, 8, 80, 65] bands with [G, GG, I, J] cups. And that's just their version of things.
There is some sense that can be done, specially for bands.. it is almost predictable, but the cups are just a total mess. So I won't be going there.
The "Italy" standard is also a bit useless as nobody seems to agree where to start off. They like to represent their sizes with roman numerals which limits their 0 size. Some say that 0 is the standard 30 band and others that 0 is 28.
The European and France systems are also a problem as I stated a couple of years ago. Right now it uses hints to figure out but I am still uneasy about the confusion.
Consider as well that manufacturers decide to switch conventions in different editions.