The recommended height for a toilet paper holder is 26 inches above the finished floor. This suggested placement comes from the National Kitchen and Bath Association.
The distance of 26 inches from floor to toilet paper holder is recommended for both standard toilets and comfort-height toilets. The NKBA also recommends that toilet paper holders are placed 8 to 12 inches in front of the toilet rim.
The placement of toilet paper holders is fairly straightforward when compared to determining the height at which to place towel bars. Considerations include the length of the towels, whether there will be enough room for the number of bars to be put up and whether the towel bars will be in the same area as robe hooks.