one aspect of the disclosure relates to a method of swinging a mobile device to simulate swinging of a golf club in order to evaluate a user &# 39 ; s golf swing for customized golf club fitting . in an embodiment , the method can be performed by a processor of the mobile device . in another embodiment , the method can be performed for multiple mobile devices concurrently , the method performed at least in part on a cloud - based server . according to an aspect of the invention , a method comprises swinging a mobile device having motion sensors integrated therein to simulate a golf swing ; evaluating the simulated golf swing to determine at least one characteristic of a custom - fitted golf club ; and outputting information related to the determined at least one characteristic . in an embodiment , the mobile device is held by a user . in an alternate embodiment , the mobile device is attached to a golf club .