Some free alarm clock apps for desktops are Alarm Clock for Windows and iTunes Alarm for Mac. The Alarm Clock app for Windows works on Windows 8 and Windows 10. It lets users choose their own alarm sounds and customize the colors and backgrounds of their alarm clocks.
iTunes Alarm for Mac allows users to configure an unlimited number of alarms and set up playlists to use as their alarm sounds. It lets users put their computers in sleep mode when they go to sleep, and it wakes up the computers as it sounds the alarms at the designated times. In addition, users can configure the snooze buttons according to their needs.