Many applications require objects that are sheets, wafers, panels, or plates of conductive or conductively coated material. For many of these applications, the resistance of the entire object (which could be a massive quantity) and/or the resistivity of the material are of secondary importance. Of primary importance is:

1. The resistance of the material as measured in the direction of its depth (the z dimension). For these users, the focus is on the material resistivity at a certain point, and they are not interested in the xy plane or the full dimensions of the sheet, disc, panel, plate, etc.
2. The resistance of the material as a sheet (any particular shape), regardless of the dimensions of the material as a whole. This is also a function of the thickness and resistivity of the material and not dependent on the size of the plane of the material.

For use in these applications, sheet resistance (Rs) was created as a unit of measurement. The inherent value of sheet resistance is that it is a measure of the electrical properties of a material independent of the xy dimensions.

Sheet resistance is resistivity divided by the thickness of the material.