Enter a start time and an end time to instantly calculate the duration between them. Works across midnight and handles hours, minutes, and seconds.
The calculator converts both times to total seconds since midnight, subtracts the start from the end, and converts the difference back into hours, minutes, and seconds. If the end time is earlier than the start time, it automatically adds 24 hours to handle overnight durations.
Duration = End Time − Start Time (in seconds), then converted to h / m / s.
For overnight durations: Duration = (End Time + 86,400) − Start Time
| Start | End | Duration |
|---|---|---|
| 9:00 AM | 5:00 PM | 8h 0m 0s |
| 8:30 AM | 12:45 PM | 4h 15m 0s |
| 10:00 PM | 6:30 AM (next day) | 8h 30m 0s |
| 7:15:30 AM | 3:45:00 PM | 8h 29m 30s |
| 12:00 PM | 12:00 AM | 12h 0m 0s |
Subtract the start time from the end time. If the minutes in the end time are smaller than the start, borrow 60 minutes from the hours. For example, 4:50 PM to 7:20 PM: borrow 1 hour, giving 80 − 50 = 30 minutes, and 6 − 4 = 2 hours. Result: 2h 30m.
If your end time is on the following day (past midnight), check the overnight box. For example, a shift from 10:00 PM to 6:00 AM crosses midnight. The calculator adds 24 hours to the end time to give the correct 8-hour result.
Yes. The result breakdown shows the duration in decimal hours (e.g., 8h 30m = 8.5 hours). This is useful for payroll or billing calculations where time is recorded as a decimal.
There are 3,600 seconds in one hour (60 seconds × 60 minutes). A full day has 86,400 seconds (3,600 × 24).
Elapsed time usually refers to time that has already passed, while duration is the length of a time interval between any two points. In practice, both terms are used interchangeably.