What should I expect my cup size to be after 325 cc implants? Currently an A cup

You did not post photos, which would have been very helpful. However, in most women, 325 cc's will increase them up to two cups.

Implant selection is an important part of high patient satisfaction after breast, augmentation surgery.
Your surgeon is responsible for helping you pick the correct implants.
Each provider will have their own way of assessing or helping patients with implant selection. Some providers will make the final decision regarding the choice of implants while other providers ask patients to choose.
There’s no right or wrong way to do this, but it is important to convey and understand what patient hopes and desires are.
Using excessively large implants leads to less natural outcomes, higher complication rates, higher revision rates and increases the chance of ultimate implant failure.
In that sense your surgeon is being appropriately cautious.
Quality breast augmentation is typically based on three variables.
The first is the patient’s candidacy for the procedure which varies substantially from one patient to another.
The second variable is the choice of implant in regards to type size and shape.
The third variable is the surgeons ability to place the implant in the anatomically correct position.
All three variables are probably equally as important.
Best,
Mats Hagstrom, MD