An interval timer is a device or application used to measure time intervals for various activities, such as workouts, cooking, or study sessions. It allows users to set specific durations for work and rest periods, helping to manage time effectively. Interval timers are popular in fitness routines, where they can guide users through high-intensity interval training (HIIT) or other structured exercises. These timers can be digital or analog and often feature customizable settings, including sound alerts and visual cues. Many smartphones and smartwatches come with built-in interval timer functions, making them easily accessible for everyday use.