rough in for a toilet replacement

replying to Richard, Iggy wrote: You can go for 12" or 13". 13" might be a bit snug , but it will work fine (the tank on a 2-piece toilet has wiggle room). However, 12" is the vastly most common and the size you'll have the most choice from and should leave you with a very normal 1" gap. I presume your existing toilet is an 11", you should be able to measure and confirm that (bolt hole to back of tank).

replying to Iggy, Norajhon wrote: To find out your toilet's rough-in, measure from the wall behind the toilet to the middle of the closet bolts, which hold your toilet to the floor. That distance will likely be a bit more than the standard 10?, 12?, or 14? rough-in dimensions. Round your measurement down to the nearest standard rough-in.