The design of a two-dimensional rotational core loss setup that considers sensor sizing and the airflux leakage field is presented. The length of the flux density (B) coils is evaluated based on the magnetic degradation caused by holes used to locate the B-coils. The measured core loss is shown to be independent of the planar magnetic field (H) coil size, but depends on the location and the thickness of the enclosed core area. This determines the extent of the airflux leakage field in the measured field. This field links through the air close to the sample surface, and is shown to bias the shape, magnitude, and phase of the measured magnetic field. Core losses measured using three testers show that the airflux leakage field reduces with increasing magnetizer diametrical size. However, it is independent of the stack length in compact magnetizers. Finally, the performance of the proposed magnetizer is assessed at 60 Hz, 400 Hz, and 1 kHz.