pre-hung door, 32x80 is that door size or total size?
 

When they sell doors and they list the size 32x80, 32x78 is that the actual door size or is that the framing too? How big should the rough opening be?

That nominal dimension is the door size, actually the interior of jambs. The door is usually 1/4" to 3/8" smaller in width than the 32". The rough opening is generally 2" to 2.5" bigger both ways.

are you sure about that?

the R.O. is 2" wider and higher than the door size.

so a 32X80 has an R.O. of 34X82 ( 82 might go higher depending on finish floor)

II Weeks, I agree with what you're saying, but I meant a good way to measure an existing door is to measure the actual door slab, which in this situation should be about 31 5/8" to 31 3/4", which = 32" prehung. It seems people get lost sometimes & think they have an odd size because the door doesn't actually = 32".