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Time DurationFree online date & time calculator — instant results, no sign-up

Calculate the elapsed time between two clock times.

Inputs

Duration
7 h 45 min
Total minutes465
Decimal hours7.75
NoteSame day

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About the Time Duration

The Time Duration calculator finds the elapsed time between a start clock time and an end clock time entered in 24-hour format. It displays the result in hours and minutes, total minutes, and decimal hours, with a note indicating whether the interval stays within the same day or crosses midnight. With the default start time of 09:30 and end time of 17:15, the duration is 7 h 45 min.

Start hour (0-23)
The hour of the starting clock time in 24-hour format, from 0 through 23, with a default of 9.
Start minute
The minute within the starting hour, from 0 through 59 minutes, with a default of 30.
End hour (0-23)
The hour of the ending clock time in 24-hour format, from 0 through 23, with a default of 17.
End minute
The minute within the ending hour, from 0 through 59 minutes, with a default of 15.

Formula and method

S = 60 × h_s + m_s; E = 60 × h_e + m_e. D = E − S when E ≥ S; otherwise D = E − S + 1440, assuming the end is on the next day. H = floor(D / 60); M = D − 60 × H; A = D / 60. With the defaults: S = 60 × 9 + 30 = 570; E = 60 × 17 + 15 = 1035; D = 1035 − 570 = 465 minutes; H = 7; M = 45; A = 7.75 hours.
  • h_sStart hour in 24-hour format.
  • m_sStart minute within the hour.
  • h_eEnd hour in 24-hour format.
  • m_eEnd minute within the hour.
  • SStart time expressed as minutes since midnight.
  • EEnd time expressed as minutes since midnight.
  • DElapsed duration in total minutes.
  • HWhole hours in the duration; floor means round down to a whole number.
  • MMinutes remaining after the whole hours are removed.
  • AElapsed duration expressed in decimal hours.

Convert both clock times to minutes since midnight, then subtract the start from the end. Under the next-day convention, add 1,440 minutes if the end clock time is earlier than the start. Divide the resulting duration into whole hours and remaining minutes, and divide total minutes by 60 to obtain decimal hours. The default inputs have an end later than the start, so no overnight adjustment is needed and the note is Same day.

Worked example

These are the calculator's starting values and the results it actually produces for them.

Inputs

  • Start hour (0-23)9
  • Start minute30
  • End hour (0-23)17
  • End minute15

Results

  • Duration7 h 45 min
  • Total minutes465
  • Decimal hours7.75
  • NoteSame day

How to use the Time Duration

  1. 1Enter the start hour and minute; the defaults are 9 and 30, representing 09:30.
  2. 2Enter the end hour and minute; the defaults are 17 and 15, representing 17:15.
  3. 3Check that hours are between 0 and 23 and minutes are between 0 and 59.
  4. 4Read the calculated duration: the default inputs produce 7 h 45 min, 465 total minutes, and 7.75 decimal hours.
  5. 5Check the day note: Same day for the default inputs; an earlier end clock time is interpreted as occurring the next day.

Reading your result

Duration shows whole hours plus leftover minutes: 7 h 45 min. Total minutes shows the same interval entirely in minutes: 465. Decimal hours shows the interval as a fractional number of hours: 7.75, where 0.75 hour equals 45 minutes. Note describes the assumed day relationship: Same day means the end time is not earlier than the start time.

Limitations

This clock-time calculation assumes ordinary 24-hour days and minute-level precision. Without date or time-zone inputs, it cannot account for daylight saving changes, time-zone differences, or intervals spanning multiple days. An earlier end time is assumed to be on the next day, and identical start and end times are treated as zero duration rather than a full day. Breaks are not deducted, so the result is elapsed time rather than net working time.

Common questions

Why does 09:30 to 17:15 give 7 h 45 min?+

09:30 is 570 minutes after midnight and 17:15 is 1035 minutes after midnight. Subtracting gives 465 minutes, which is 7 whole hours and 45 remaining minutes.

Why is the decimal-hours result 7.75 rather than 7.45?+

Decimal hours express minutes as a fraction of an hour. The 45-minute remainder is 45 ÷ 60 = 0.75 hour, so the result is 7.75 hours.

How is an end clock time earlier than the start handled?+

It is interpreted as an end time on the following day. The calculation adds 1,440 minutes to the clock-time difference to account for crossing midnight.

Does the default duration represent paid working time?+

Not necessarily. The 7 h 45 min result includes the entire interval from 09:30 to 17:15; any unpaid breaks must be deducted separately.

Does the calculator save my information?+

Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.

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Results are estimates for informational purposes and are not financial, medical or legal advice.