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'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.