Caliper is the thickness of a sheet of paper expressed in thousandth of an inch. This measurement is taken with a micro meter. Normally, paper caliper should not have more than a plus or minus 5% variance within a sheet. Usually the greater the caliper (the thicker the paper), the greater the paper weight but this depends on the density and finish of the paper. Therefore, the following chart is meant to be approximate. Every Paper.com paper shows the caliper for that particular paper.

The basis weight of a paper is the weight of 500 sheets, measured in pounds, in that paper's basic sheet size. It is important to note that the "basic sheet size" is not the same for all types of paper and it is never 8 1/2 x 11. 8 1/2 x 11 is the result of cutting a Basic Sheet of Bond paper.

While different paper types have different basic sizes, papers can still be compared by using equivalent weight. In this example a 24 pound bond has the equivalent weight as 60 pound offset.