It’s so bad that my fiancée has some bras that say she’s a B cup and others that says she’s a D cup. In order to go bra shopping, you have to actually try them on to find out if they fit.
If I had to try on underwear to see if they fit, I might not bother with underwear at all!
The cup size SHOULD be the difference in inches between the circumference below the breast and circumference around the breast.
3" difference would be a C cup
5" would be DD.
Why they double up some letters and not others, I couldn’t tell you. 🤷🏻♂️
My ex used to sell underwear.