Time Duration Calculator — Elapsed Time Between Two Times
Enter a start and end date and time to get the exact elapsed duration — broken down into days, hours, minutes and seconds, plus a decimal total in hours and minutes. Overnight spans (an end time earlier in the clock than the start, on the next day) are handled correctly as long as the end date is set one day later. Everything runs in your browser; nothing is sent to a server.
About the time duration calculator
A time duration calculator finds the exact elapsed time between a start and end date/time — broken into days, hours, minutes and seconds, plus a decimal total. Set the end date one day later than the start to correctly handle an overnight span.
Mental time subtraction slips easily, especially past midnight. Enter a start and end date/time to get the exact gap in days, hours, minutes and seconds, plus a decimal-hours total for logging or billing.
Worked examples
| Start | End | Duration |
|---|---|---|
| 9:00 AM | 5:00 PM | 8h 00m |
| 9:00 AM | 5:30 PM | 8h 30m |
| 10:30 PM | 6:15 AM | 7h 45m (overnight) |
| 11:00 PM | 7:00 AM | 8h 00m (overnight) |
How to calculate elapsed time by hand
Subtract start from end, minutes first. For 9:40 to 13:15: 15 minus 40 will not go, so borrow an hour: 75 minus 40 = 35 minutes, and 12 minus 9 = 3 hours. Elapsed: 3 hours 35 minutes.
Across midnight, split it: 22:30 to 06:15 is 1h 30m before midnight plus 6h 15m after, 7 hours 45 minutes. The calculator handles this when the end date is the next day.
From elapsed time to decimal hours
Payroll and billing tools want decimal hours: divide minutes by 60 and add to the hours, so 3h 35m = 3 + 35/60 = 3.58 hours. The total hours line under the result shows this, and the decimal hours converter has a full chart.
Adding several durations together
Add hours and minutes separately, then carry every 60 minutes into an hour. 2h 45m + 1h 30m + 0h 50m is 3 hours and 125 minutes, which becomes 5 hours 5 minutes. For adding time to a clock time or date, use add or subtract time; for a week of work shifts with breaks, the hours calculator is faster.
Common mistakes
The most common error is treating minutes as hundredths: 1:50 to 2:20 is 30 minutes, not 70. Next is mixing up AM and PM. If the answer looks too long or negative, check the end date, especially for night shifts and events crossing midnight. Flights across time zones need local times converted first; the time zone converter helps with that.
When to use it
- Logging how long a task, meeting or work session actually took.
- Checking a delivery or travel window between two timestamps.
- Working out how long is left in an event that started at a known time.
- Cross-checking a timesheet entry someone else filled in.
How to use it
- Enter the start date and time.
- Enter the end date and time — set the end date a day later if the span crosses midnight.
- Read the result in days/hours/minutes/seconds, or use the decimal total for logging.
Tips
- If your result looks negative or huge, check whether the end date needs to be the next day.
- Use the decimal-hours total (e.g. 3.75) when pasting into a spreadsheet or invoice.
FAQ
How do I calculate the duration between two times?
Enter a start date and time, and an end date and time. The calculator subtracts one from the other and shows the result in days, hours, minutes and seconds.
Does this handle overnight spans, like 11pm to 6am?
Yes — enter the end date as the next day and the calculation is exact.
How many hours is 9 to 5?
Eight hours, before any unpaid break is deducted. With a 30-minute unpaid lunch it is 7 hours 30 minutes of paid time, which is why timesheets ask for the break separately.
How do I calculate hours worked on an overnight shift?
Enter the start and end time as normal. An end time earlier than the start is treated as overnight, so 10:30pm to 6:15am returns 7 hours 45 minutes rather than a negative result.
How do I convert the result into decimal hours for payroll?
Divide the minutes by 60: 45 minutes becomes 0.75, so 7 hours 45 minutes is 7.75. Minutes are out of 60 rather than 100, which is why 45 minutes is not 0.45.
How do I add hours and minutes together?
Add hours and minutes separately, then turn every 60 minutes into one hour. For example 2h 45m + 1h 30m = 3h 75m = 4h 15m.
How many hours is 9 AM to 5:30 PM?
8 hours 30 minutes, or 8.5 decimal hours. Subtract any unpaid break to get the hours worked.