Inductively coupled power transfer systems (ICPT) are becoming ubiquitous in industry. Many such systems are excited with single or multi-phase input current. This leads to increased complexity in comparing such systems when solely using the magnetic frequency analysis. This paper utilizes modern finite element method analysis software to propose a novel software methodology for the numerical comparison of single and two phase ICPT systems as demonstrated on a three dimensional (3D) battery charging system. The sinusoidal magnetic frequency response of a single phase system is compared to the magnetic transient response of a multi-phase current system by use of a novel software methodology proposed in this paper. This consists of a transient response analysis to determine compute the resulting magnetic response over the duration of an input current period on the two phase system. The resulting non-sinusoidal response is then integrated over a whole period to extract the root-mean-square value for comparison with that of a single phase system across a 3D cubic power zone.