Touch sensors are built using conductive materials on a transparent substrate. The resistance of these materials is measured in Ohms per square, meaning that a square of the material has the same resistance regardless of its size. The resistance of rectangular shapes can be easily calculated. Calculating the resistance of non-rectangular shapes is more difficult. A derivation is given for estimating the resistance of a standard diamond pattern used in touch sensors. Indium tin oxide (ITO) is the most commonly used transparent conductor. Other types of transparent conductors include carbon nanobuds, metal mesh, silver nanowire, and others.