Enter a start time and end time to calculate the exact time duration between them. Choose between 12-hour (AM/PM) or 24-hour format, include optional seconds, and get results broken down into hours, minutes, and seconds — plus the total in decimal hours.
Time Duration
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Total Hours
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Total Minutes
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Total Seconds
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Decimal Hours
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If your end time is earlier than your start time (e.g. start at 10:00 PM and end at 6:00 AM), the calculator automatically assumes the end time is on the following day and calculates the duration accordingly. This makes it useful for overnight shifts, sleep tracking, and similar scenarios.
The 12-hour format uses AM and PM to distinguish between morning (12:00 AM to 11:59 AM) and afternoon/evening (12:00 PM to 11:59 PM). The 24-hour format (military time) runs from 0:00 to 23:59 with no AM/PM distinction. Select whichever format matches the times you're working with.
Convert both times to 24-hour format, then subtract the start time from the end time. If the result for minutes or seconds is negative, borrow 60 from the next higher unit. For example, from 8:45 AM to 5:30 PM: convert to 08:45 and 17:30, then subtract to get 8 hours and 45 minutes.
Decimal hours express time as a single number rather than hours and minutes. For example, 1 hour 30 minutes equals 1.5 decimal hours. This format is especially useful for payroll calculations, billing, and time tracking systems that require numeric hour entries.
This calculator is designed for durations within a single day or spanning one overnight period (up to roughly 24 hours). For durations spanning multiple days, use a date-and-time duration calculator that accepts full date inputs alongside the time.
12:00 AM is midnight (the start of the day) and 12:00 PM is noon (midday). This is a common source of confusion in the 12-hour clock system. In 24-hour format, midnight is 00:00 and noon is 12:00, which removes the ambiguity entirely.
Enter your shift start time in the Start Time fields and your shift end time in the End Time fields. Select AM or PM (if using 12-hour format) and the calculator will show you the total hours and minutes worked — including overnight shifts where the end time falls on the next day.
Yes. Both the Start Second and End Second fields are available if you need precision to the second. If seconds are not relevant to your calculation, simply leave them at 0 and the result will be expressed in hours and minutes only.