Enter a start time and an end time to calculate the time difference between them. Choose 12-hour (AM/PM) or 24-hour format, and the calculator returns the difference in hours, minutes, and seconds — even when the end time crosses midnight into the next day.
Total Duration
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Hours
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Minutes
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Seconds
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Total Seconds
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Total Minutes
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When the end time is earlier than the start time (for example, 10:00 PM to 6:00 AM), the calculator automatically assumes the end time is on the following day. It adds 24 hours to the end time before subtracting, so you always get the correct forward-going duration.
The 12-hour format uses AM (midnight to noon) and PM (noon to midnight) designators, running from 1:00 to 12:59. The 24-hour format (also called military time) runs from 0:00 to 23:59 with no AM/PM needed. This calculator uses 12-hour format with AM/PM selectors.
Convert both times to a common 24-hour format, then subtract the start time from the end time. If the seconds or minutes of the start are larger than those of the end, borrow from the next unit (e.g., borrow 60 seconds from minutes). If the end time total is less than the start time total, add 24 hours to account for crossing midnight.
Yes. Enter your clock-in time as the start time and your clock-out time as the end time. The result shows your total shift duration in hours, minutes, and seconds — useful for timesheets and payroll calculations.
Decimal hours express the duration as a single number where the fractional part represents minutes and seconds as a fraction of an hour. For example, 8 hours and 30 minutes equals 8.50 decimal hours. This format is commonly used in billing and payroll systems.
12:00 AM is midnight (the start of the day, equivalent to 0:00 in 24-hour time), and 12:00 PM is noon (equivalent to 12:00 in 24-hour time). These are common sources of confusion — the calculator correctly converts both when computing the difference.
The calculator is designed for durations within a single 24-hour period, so the maximum result is 23 hours, 59 minutes, and 59 seconds. For differences spanning multiple days, consider using a date and time duration calculator instead.
They actually do — the total seconds equals total decimal hours × 3600, and the hours/minutes/seconds breakdown is just that same value expressed in its natural units. For example, 5400 total seconds = 1 hour, 30 minutes, 0 seconds = 1.50 decimal hours.