**Solar Panel Calculator** is an online tool used in electrical engineering to estimate the total power output, solar system out put voltage and current when the number of solar panel units connected in series or parallel, panel efficiency, total area and total width. These estimations can be derived from the input values of number of solar panels, each panel unit power and voltage, width and height of the panel and the wiring type. Solar panel calculator sometimes also called as solar panel estimator. Because these are all the estimation not that accurate values of output due to its power and voltage losses of the circuit. In order to estimate how many solar panels are required to produce determined output quantities, all the above said calculations should be taken into consideration