This is a question where the question should be how long are you going to wait to take the measurement. But there have been cases where a person waited 416 days to see what happened when the timer exceeded 9,999 hours.

In real life, stopwatches are normally used to measure time intervals that are not that long.

In analogue stopwatches, the maximum time limit is usually 30 minutes, although some more sophisticated models manage to keep more time.

In our online stopwatch tool, the limit is 99 hours (4 days).