While it seems like placing a toilet paper holder should be a simple procedure, deciding where to place it takes time. Consider who will be using the toilet paper. For example, if a disabled person is going to be using the facilities, the paper holder may need to be located closer to the toilet or lower than usual. Similarly, if the toilet is closely boxed in on three sides, a normally placed paper holder may knock into people's knees or elbows as they rise.
The priority when placing a toilet paper holder is comfort. Sit on the toilet and close your eyes. Then reach your hand out toward the place where you expect the toilet paper to be. For a very precise test of whether that location will be acceptable, stick the toilet paper holder complete with toilet paper to the wall with sticky tack. While sticky tack will not hold the object there long, it will allow you to go through the movements near the toilet to check for placement.
Starcraft Custom Builders states that the toilet paper holder should be located 26 inches above the floor and 8 to 12 inches in front of the toilet bowl. This measurement suits a wide variety of homes. If you have the space, these measurements allow you to reach very naturally for the toilet paper.
A freestanding toilet paper holder allows you to avoid mounting anything to your wall at all. While it takes up more floor space, it also allows you to house several rolls of toilet paper neatly and attractively close to the toilet. Place the freestanding paper holder out of the path of traffic and as close to the toilet as you can without crowding it.