A floating floor system and a floor panel and method for use with the same that includes an improved mechanical interlock system. The mechanical interlock system allows laterally adjacent floor panels that are mechanically interlocked to slide relative to one another a predetermined distance in a longitudinal direction, while prohibiting relative translation in the vertical and transverse directions. In one embodiment, the predetermined distance eliminates the need for precision cuts during installation, thereby making installation fast and easy. In a further embodiment, the invention optimizes the floor panels (and floating floor system.) to balance ease of installation and horizontal locking strength between laterally adjacent floor panels.