Date and Time Duration Calculator
Find the time between two dates with clock times: total hours, plus the breakdown into days, hours and minutes, total minutes and weeks. For spans longer than a day, such as a rental, a shift roster or a countdown.
Last updated: October 2026
Total hours
56.5 hours
Formula below · 3 sources (NIST, aa.usno.navy.mil, iso.org) · Updated Oct 2026
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About this calculator
Each date and time is turned into a single number of minutes: the calendar date as whole days from a fixed epoch, plus the clock time as minutes since midnight. The end is subtracted from the start, and the difference is given as total hours (the headline), and broken into whole days, remaining hours and remaining minutes, as well as total minutes, decimal days and weeks.
The arithmetic is done on calendar days, not on local wall-clock time, so a daylight-saving change inside the span does not add or remove an hour. If you need the exact elapsed time across a DST switch (for instance for a 48-hour sample started the night the clocks go forward), subtract or add that hour by hand.
If the end is before the start the result is negative. For two clock times on the same day the hours calculator at /en/calculators/time-zones/time-duration-calculator/ is simpler, and for whole dates only the day counter at /en/calculators/time-zones/day-counter/ counts calendar days.
How to use
Enter the start date and time and the end date and time. Dates are YYYY-MM-DD; times can be 9:00 AM, 5:30pm or 17:30. Example (the defaults): Friday 2026-10-23 at 9:00 AM to Sunday 2026-10-25 at 5:30 PM. The dates are 2 days = 48 hours apart, and 5:30 PM is 8 hours 30 minutes after 9:00 AM, so the span is 56.5 hours: 2 days, 8 hours and 30 minutes, or 3,390 minutes. Example: a car rental picked up 2026-03-06 at 2:00 PM and returned 2026-03-09 at 10:00 AM. Three days would be 72 hours; 10:00 AM is 4 hours before 2:00 PM, so the rental ran 68 hours = 2 days 20 hours, which a rental company bills as three 24-hour days.
Frequently asked questions
How many hours are there between two dates?
Multiply the number of days between the dates by 24, then add the difference between the two clock times (subtracting if the end time is earlier in the day than the start time). 2026-10-23 9:00 AM to 2026-10-25 5:30 PM is 2 × 24 + 8.5 = 56.5 hours.
Does the result account for daylight saving time?
No. The span is computed on calendar dates and clock times, so it answers "how many hours on the clock". Across a DST change the true elapsed time differs by one hour: add an hour when the clocks fall back inside the span, subtract one when they spring forward.
Why is the result negative?
The end date and time are earlier than the start. Swap them, or read the negative number as "that long ago".
Can I enter 24-hour times?
Yes: 17:30, 17.30 and 1730 all mean 5:30 PM, 0:00 is midnight at the start of the date and 24:00 is midnight at its end.
How do I convert the decimal hours to hours and minutes?
Take the fractional part times 60. 56.5 hours → 0.5 × 60 = 30 minutes, so 56 hours 30 minutes. The tiles under the result do this and also split off whole days (56.5 h = 2 days 8 h 30 min).
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Sources & references
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