Use the timer or stopwatch on iPhone
In the Clock app , you can use the timer to count down from a specified time. You can also use the stopwatch to measure the duration of an event.
Ask Siri. Say something like: “Set the timer for 3 minutes” or “Stop the timer.” Learn how to ask Siri.
Set the timer
Set the duration of time and a sound to play when the timer ends.
Tip: If you want to fall asleep while playing audio or video, you can set the timer to stop the playback. Tap When Timer Ends, then tap Stop Playing at the bottom.
The timer continues even if you open another app or if iPhone goes to sleep.
Track time with the stopwatch
Tap Stopwatch. To switch between the digital and analog faces, swipe the stopwatch.
The timing continues even if you open another app or if iPhone goes to sleep.
To record a lap or split, tap Lap.
Tap Stop to record the final time.
Tap Reset to clear the stopwatch.