A 34C and a 32D are actually the same size cup size. ... A 34C and a 32D are known as "sister sizes" which means that the cup will fit the same amount of breast tissue and the same applies for their other "sister sizes" of a 36B, 38A, 32D, 30DD, 28E.
Is D cup size big?
For some reason, we have been brainwashed into thinking that boob sizes go from A-DD, DD being the biggest boob/bra size. DD is actually at the lower end of the scale, there is still E, F, FF, G, GG, H, HH, J, JJ, and K cup above that. ... This means that any other band in that same bra style won't fit you properly.