Calculate the exact duration between two times, even across midnight
This time duration calculator computes the exact hours, minutes, and seconds between a start time and an end time. It automatically handles overnight periods (past midnight) and displays results in both 12-hour and 24-hour formats.
Enter the start and end times using the hour, minute, and second fields along with AM/PM selection. Click Calculate to see the duration. If the end time is earlier than the start time, the calculator assumes the end time is on the next day (overnight).
When the end time is earlier than the start time, the calculator adds 24 hours to the end time before computing the difference. This correctly handles shifts or events that start in the evening and end the following morning.
The calculator uses 12-hour format with AM/PM for input. However, the results show the duration in both 12-hour and 24-hour display formats for your convenience.