A timer is a software program or hardware device that keeps track of the elapsed time between two events. A timer may also measure a specified amount of time, and signal the user when the “time is up.” Uses of a timer include measuring the elapsed time between the start and end of a computer program, or the elapsed time between two mouse button clicks.
An example of a software timer is a tomato clock, used in the pomodoro method of time management.
Software terms, Time
You can find different software timers by searching the Internet for software timer or software countdown.