Every bathroom is different, so you should make sure that the toilet you choose can fit in the space you have available. If it doesn’t, this can cause a lot of issues and require pricey modifications. The best solution is to measure the space you have available while your old toilet is still in place. You will need to measure the distance from the bolts that hold your toilet in place on the floor to the wall behind it. In most bathrooms, this distance will be 12 inches, but it could also be 10 or 14. If the old toilet has already been removed, measure the distance between the wall and the center of the drainpipe.