I've been very confused about what size bra to wear lately! Before the measurement calculator, I had been unhappily wearing a 32A. I then tried on a ton of bras one day at Aerie and eventually was very happy with a 32C. In particular, I wore Aerie's Sunnie Full Coverage. A little while later, I went to the calculator I'm a 28DD. I have no problem believing this! I was still very happy with how my 32Cs fit, very comfortable, no gapping, etc. I guess the only this is that the straps were a little wide set. But I decided if I could get a good deal, I would try smaller band sizes.

I recently saw Aerie added Demi and Racerback versions of the Sunnie online, so I took the opportunity to try a smaller sister size, 30D. They arrived today, and they didn't fit so great. With the first (regular demi), the band felt tight, even on the largest clasp. The cups seemed to fit so-so, but weren't as "perfect" as the 32C full coverage. The second (racerback), there was only a front clasp, and it was really digging into my ribcage. The cups also seemed too small, as my breast tissue was bulging out over the top a bit. Theoretically, a 30D should be closer to my actual 28DD than a 32C, right? Yet I found the 32C to not only fit better, but be more comfortable.

I'm thinking of exchanging for a 32C, but I feel guilty because it's technically "more wrong"?? Is there any explanation for what went wrong? Is it just Aerie's cuts and sizing being weird, and I should ditch the mainstream bras?

Sorry this turned out so long! I was afraid it wasn't a well thought out enough question for its own post...