Time Duration Calculator

Time duration calculator at a glance#

How many hours is 0700 to 1530?#

From 0700 to 1530, it is 8 hours and 30 minutes, which is equivalent to 8.5 hours or 510 minutes. In 24-hour time, 0700 is 7:00 am and 1530 is 3:30 pm. You can enter them in the calculator as 07:00:00 and 15:30:00.

How do you calculate the duration between two times?#

To find the time duration, subtract the start time from the end time: seconds from seconds, minutes from minutes, and hours from hours. Borrow 60 when a column comes up short. If the end time is earlier than the start time, the duration spans past midnight, so adding 24 hours to the end time before subtracting is necessary. The calculator handles these steps automatically.

How do you find the time between two dates and times?#

First, count the hours to the first midnight, then the full days in between, and finally the time on the last day. For instance, from Monday, October 12, 2026 at 21:40 to Wednesday, October 14, 2026 at 06:15 you get 2 hours and 20 minutes, plus one full day, plus 6 hours and 15 minutes. Altogether, it's 1 day 8 hours and 35 minutes, or 32 hours and 35 minutes total. The Between Two Dates tab calculates this directly.

What a time duration is#

A time duration is the time elapsed between a start and an end. A time of day, such as 21:40, identifies a specific moment. A duration, like 8 hours and 35 minutes, measures a length of time and can extend beyond 24 hours.

Durations are measured in days, hours, minutes, and seconds. A day has 24 hours, an hour has 60 minutes, and a minute has 60 seconds, so a full day contains 86,400 seconds. With steps of 24 and 60 instead of 10, borrowing and carrying become necessary in calculations.

The example used here is a night shift starting Monday, October 12, 2026 at 21:40 and ending at 06:15. We work it out from the clock times first, then with dates, running to Wednesday morning.

Calculating a duration by hand#

When both times are on the same day, subtract each column separately. From 07:00 to 15:30, hours give 15 minus 7 which is 8, and minutes provide 30 minus 0 which is 30. Thus, the duration is 8 hours and 30 minutes.

If the end time is earlier, the period crosses midnight. The Time Duration tab treats the end time as the next day, so 21:40:00 to 06:15:00 gives 8 hours 35 minutes. The hours calculator page walks through overnight shifts step by step.

Durations across dates#

Clock times alone cover at most one day, so a period spanning multiple dates requires dividing into three parts: remaining time on the start day, full intervening days, and the time on the final day.

For a shift starting Monday at 21:40 and ending Wednesday at 06:15:

• Monday, 21:40 to midnight, is 2 hours and 20 minutes.
• Tuesday accounts for 24 hours.
• Wednesday, from midnight to 06:15, is 6 hours and 15 minutes.

In total, the duration is 32 hours and 35 minutes, which the calculator represents as 1 day 8 hours and 35 minutes. Fully converted, that's about 32.58 hours, 1,955 minutes, or 117,300 seconds. The Between Two Dates tab handles this with start and end inputs.

For whole days between two dates, without the clock times, the date calculator counts them directly.

Reading 24-hour and military times#

Duration queries often involve 24-hour or military time, where hours run from 00 to 23 without am or pm indicators. 0700 corresponds to 7:00 am, 1530 is 3:30 pm, and 1930 is 7:30 pm. To convert a pm time from the 12-hour clock, add 12 to the hour: 5:45 pm becomes 17:45.

Input times as hh:mm:ss with colons between parts, so 1530 should be 15:30:00. The Now, Midnight, and Noon links fill in common times efficiently.

Seconds#

The calculator includes seconds. From 08:52:00 to 13:37:13, the duration is 4 hours, 45 minutes, and 13 seconds. To calculate manually, start with seconds: 13 minus 0 gives 13 seconds. Next, the minutes: 37 minus 52 requires borrowing, so 13:37 is converted to 12 hours and 97 minutes. Finally, 97 minus 52 gives 45 minutes, and 12 minus 8 gives 4 hours.

Daylight saving time and time zones#

The calculator measures by clock time and doesn't adjust for time zones or daylight saving time, which typically doesn't affect results except on days when clocks change. In the US, daylight saving time ends at 2:00 am on the first Sunday in November, when clocks fall back an hour. For example, on November 1, 2026, a shift from 22:00 on Saturday to 06:00 on Sunday appears as 8 hours on the clock, but 9 hours actually pass. In March, the reverse happens, shortening the night by an hour.

Travel across time zones requires converting both times to the same zone before subtracting. A flight departing New York at 08:00 and arriving in Los Angeles at 11:15 local time means adjusting for Los Angeles being 3 hours behind, so the landing time is 14:15 New York time. 14:15 minus 08:00 gives a 6-hour 15-minute flight.

Breaks are not taken off#

A duration spans the entire time from start to end. The calculator does not account for lunch or rest breaks, so you must deduct any unpaid break time yourself. An 8-hour 35-minute night shift with a 30-minute unpaid meal break translates to 8 hours and 5 minutes worked.

To total a week of shifts with a break on each day, use the work hours calculator.

Where a time duration calculator helps#

• Shift and on-call durations, particularly overnight ones using military time.
• Flight, train, and drive times once both ends are synchronized to the same time zone.
• Timing races, cooking, experiments, or anything requiring precise second-level measurement.
• Counting hours between events a few days apart, such as from a deadline to a delivery.

Durations between common 24-hour times#

These pairs come up often in military and 24-hour time. The last two cross midnight.

Sources#

• NIST Guide to the SI, Chapter 5: Units Outside the SI (Table 6: minute, hour, day)
• NIST, Daylight Saving Time Rules

Frequently asked questions#

How do I calculate time duration in military time?#

Write both times with colons, such as 06:00 and 19:30, then subtract hours and minutes. From 0600 to 1930, it is 13 hours 30 minutes. If the end time is earlier, add 24 hours to the end first.

Can the calculator include seconds?#

Yes, it can. Enter times as hh:mm:ss. From 08:52:00 to 13:37:13, you get 4 hours, 45 minutes, 13 seconds.

What is 30 minutes from 11:45?#

Adding 30 minutes to 11:45 results in 12:15. 45 plus 30 is 75 minutes, 1 hour 15 minutes, so the time is 12:15. The calculator measures time between two points, so manually adding a fixed number of minutes is quickest.

How do I get the duration in total hours or minutes?#

To find the total, multiply the days by 24, add the hours, then multiply by 60 and add the minutes for a total in minutes. 1 day 8 hours 35 minutes equals 32 hours 35 minutes, or 1,955 minutes. The hours and minutes calculator also provides these totals for dates and times.

Does daylight saving time change the result?#

Clock time is used, so the calculator doesn't account for the hour added or subtracted when clocks change. For periods crossing a change, add an hour in November or subtract one in March for accurate elapsed time in the US.