Currently,　there　is　no　standardized　approach　for　evaluating　the　efficiency　of　planar　wireless　power　transfer　(WPT)　systems　across　varying　specifications　and　sizes,　particularly　under　positional　deviations.　This　paper　introduces　an　innovative　approach　to　assess　the　positional　tolerance　of　single-transmitter,　single-receiver　planar　magnetically　coupled　resonant　wireless　power　transfer　(MCR-WPT)　systems.　We　present　a　normalized　effective　working　range　that　quantifies　the　operational　range　of　different　MCR-WPT　systems　where　transmission　efficiency　degradation　is　limited　to　a　specified　value,　such　as　sigma%.　This　approach　measures　the　system＇s　resilience　to　coil　misalignment　and　identifies　key　parameters　influencing　transmission　efficiency.　The　practicality　and　effectiveness　of　the　proposed　method　are　demonstrated　through　experimental　validation.