• the voltage spread: the difference between the voltage extremes. To estimate the cell capacity, VOLTA calculates the capacity of both the positive and negative electrodes; the lower of the two limiting the capacity of the cell overall. While it is easy to prove that cell capacity is directly proportional to the product of the AM's specific capacity and of its density (eq. 1), the goal of VOLTA is to provide reasonable experimental-like values, to facilitate the comparison between theoretical and real world cells.