Calculate the duration between two dates and times
- Enter a start date and time, then an end date and time. Seconds are optional.
- Choose a 12-hour or 24-hour clock. Both times change format together.
- Read calendar months, remaining days, hours, minutes and seconds, alongside totals in each fixed-length unit.
- Copy the result with its dates and calculation assumptions. Swap the endpoints or clear the calculation when needed.
Formats, output and limits
Gregorian calendar dates from 0001-01-01 to 9999-12-31, with whole-second times. Calculation is local and independent. No automatic saving or data in URLs. Days are 24 hours; no time zone, DST or leap-second adjustment is applied.
A worked example
From 09:00 to 17:30 on the same date is 8 hours 30 minutes, or 510 minutes. From 22:00 to 06:00 the next day is 8 hours, or 28,800 seconds. For longer spans, the result also shows full calendar months and the remaining days.
Common questions
How do I calculate the time between two times on the same day?
Choose the same start and end date, then enter both times. Use total minutes for the entire interval, or read the hours and minutes in the calendar breakdown.
How do I calculate time across midnight?
Choose the following date for the end time. The overnight example fills in both dates so you can see which date changes.
How are months calculated?
Months follow Gregorian calendar dates rather than a 30-day average. Month-end intervals can remain in days: 31 January to 28 February 2026 at the same time is 0 months and 28 days. The fixed-day and exact-second totals describe the same interval.
Are daylight-saving changes included?
No. This calculator compares calendar dates and wall-clock times without a time zone, treating every day as 24 hours. It does not calculate travel time between zones or adjust for daylight-saving transitions.
Is the end date included as another full day?
No. It measures from the specified start time to the specified end time. Identical dates and times give zero; midnight to midnight on the next date gives 24 hours.
Can I calculate durations longer than a day?
Yes. Select both dates. Months may span multiple years, and totals include every calendar day. An end before the start is highlighted; it is never silently moved to the next day.