A lot of clock applications
Numerous clock apps are available for smartphones, allowing users to use them as both a clock and a screen savor. However, most of these apps do not display time in increments smaller than seconds. In situations where a more precise time check is required, such as with timers or stopwatches, milliseconds become crucial.
Millisecond Clock
The millisecond clock that displays time down to the millisecond has been released for the iPhone. Just like its Android counterpart, it is free and easy to use.