The elapsed time is calculated at the start time and the finish time.
When the start time and the finish time are selected, and "Calculate time" button is clicked, the elapsed time from the start time to the finish time is calculated and displayed.
When the finish time is earlier than the start time, the finish time is calculated as the next day.
Moreover, the elapsed time is displayed by "the hour, minute, and second", the hour conversion, the minute conversion, and second conversion.