This tool reads your MOV video directly in the browser and encodes a MP4 copy, so there is no upload, no queue and no waiting for a server. It works on desktop and mobile.
MOV files from iPhones and Macs often will not play in Windows players, web uploads or older Android phones. MP4 with H.264 video and AAC audio plays practically everywhere.
Converting re-encodes the video, so it can take about as long as the clip itself. Keep the tab open until it finishes.