How to figure out the best price on toilet paperFiguring out the best price on toilet paper is made difficult by the huge variety in products, sheet size, and roll size. As a rule of thumb, in the US in 2007 you should not be paying more than $0.25 per regular size roll. With coupons and sales you can probably get even less expensive. It usually sells for more than this, but if you pay more, you definitely are not getting a good deal. But what about double rolls and mega rolls, etc - well then you can do the math with the help of the information below to decide what the roll is really worth.
Roll SizesThere are many dimensions to roll size, essentially the amount of paper you get. Today's (2007) standard width of a roll in the U.S. is 4.5 inches. The other dimension will vary both in the size of each sheet, the number of sheets, and the length of the roll (but the sheet count times the size of the sheet will always give you the length of the roll and when multiplied by the width of the roll it will give you the dimention in square feet or meters that is used for the unit measure printed on the package, and on the store shelf).
Manufactueres have started to offer rolls that they claim have more paper. Within the brand, you can usually rely on their characterizations, such as that a double roll will have twice the paper as the single or standard roll of the same brand, and that jumbo, giant, or mega rolls have the claimed multiplier applied (e.g. Charmin has jumbo and giant rolls that are 2.5 times larger than their standard rolls). While these are the claimed multiplier larger than their standard rolls of today, there is nothing that keeps them from reducing the size of the standard roll (and thus the base figure that is multiplied). Today if you used a standard roll, you find yourself replacing the roll way too frequently, and more frequently than you might have done using standard rolls from the days when all rolls were standard.
I believe that most people use toilet paper by length drawn off the roll, or by depth when folded, rather than by sheet count, so that means that you can judge the relative amount between packages by the square footage (as long as the width of the roll is the standard 4.5 inches).
Number of PliesIf the roll is two ply it may reduce the amount used, but plies in such rolls are usually thinner than single ply sheets, so it doesn't quite equal twice the depth of that of the same amount of a single ply. One or two ply does affect percieved softness and quality, so it is likely more of a personal preference and comparisons are more accruate with other rolls of the same "one or two ply" characteristic. Often a single brand will have both one and two ply varieties, for example, both Charmin and Cottenelle have two ply versions that they call "ultra".
Some NumbersHere are some of the numbers I recall reading off of packages in early 2007. I apologize in advance for any errors in my numbers, or in my calculations.
My early 2007 numbers for the Cottonelle Ultra double ply roll has 200 (4.5 x 4.0 inch) sheets for a total area of 2.3 square meters according to the package (2.32 by my calculation). By calculation, I presume that the single two-ply roll would be 1.16 square meters with 100 sheets. I do not know if they have similarly reduced the size of these rolls.
What is a standard rollThere is no standard size roll, but based on the measurements above, and as a rule of thumb for comparison I use the following: A standard rolle of single-ply toilet paper would be 2 square meters, and for double ply it would be 1.15 square meters.
Using the measurements from early 2007 listed above, I would apply the following approximate multipliers to the following products (i.e. one roll of the product is approximately the same as X standard rolls).