A system and method to automatically determine power plane shape in a printed circuit board (PCB) involve obtaining inputs. The inputs include a size and shape of the PCB, a set of sources, and a set of sinks associated with a power plane. The method also includes determining a center of charge (CoC) as a center of largest current density for the set of sources and the set of sinks, and creating a sub-shape corresponding with a path from each source of the set of sources and from each sink of the set of sinks to the CoC. The creating the sub-shape includes determining a width of a conductor in the path corresponding with each of the sub-shapes. The sub-shapes created for the set of sources and the set of sinks are combined as the power plane shape.