Hi again emma! When I was looking for my post op bra (when i was pre-op) I took my rice-test rice and tried them inside the bras to see what fitted best! It did work too! I’d think at a guess for you, 32c or 32d. I didn’t find I needed a bigger back size as it was only my boobs that grew lol however lots of the girls on hear say they needed a bigger back size for the swelling! Hope that helps! Good luck! xxx