Software that can be run for a limited period of time before it expires and ceases to operate. In order to keep running the application, a registration key (password) must be purchased and entered into the trial version, or a new, full version must be installed. Trialware may be set up by date or days. For example, a 30-day trialware program may expire in 30 days or after it has been used for 30 non-contiguous days.

Also called "demoware," sophisticated trialware prevents a user from continuously obtaining new copies without paying. For example, it can check for an entry to the Registry or the existence of a hidden file that was created by any previous installation of the trialware. See shareware.