In article , Mikepier wrote:
I was shopping in Lowes tonight for a basic toilet to replace an old
one we have in a rental. The original one in the rental is 10" rough
when I measured from the flange studs to the wall. Lowes only sells
12" rough-in in stock, however the toilets they had on display I
measured just for curiousity, and most actually measured about 10"
from the flange holes to the back of the tank. So I'm just wondering
why they do this?

Why do they do what? Give accurate dimensions? The rough-in dimension is the
distance from the *centerline* of the opening to the wall. Since the opening
is 4" in diameter, hence 2" in radius, the distance from the *edge* of the
opening to the back of the tank is *supposed* to be a bit less than 10" for a
12" rough-in.