Working with time periods that exceed 24 hours in Excel for Mac

Article translations Article translations
Article ID: 190633 - View products that this article applies to.
This article was previously published under Q190633
Expand all | Collapse all

On This Page


In Microsoft Excel, you can format a cell containing the sum of amounts of time that exceed 24 hours with the number format "[h]:mm:ss"; Microsoft Excel automatically adds times beyond 24 hours and formats them correctly.


To add times with a sum that exceeds 24 hours, use a normal sum formula:
Then, click Cells on the Format menu, click the Number tab, click Custom in the Category list, and choose the following number format:
This format works correctly with times that exceed 24 hours.

Note Range is either the defined name of a range that contains the times or the cell reference of the range that contains your times (for example, A1:A4). The values in the range must be in the "h:mm" or "hh:mm" format.

How Microsoft Excel interprets times

Microsoft Excel uses a serial numbering system to calculate dates and times. In this system, a single day is equal to one unit of time. Because an hour is equal to one twenty-fourth of a day, the serial number equivalent of one hour is 0.041667 (1 day divided by 24 hours in a day). Following the same logic, the serial number equivalent of one minute is 0.0006944 (1 day divided by 1,440 minutes in a day), and the serial number equivalent of one second is 1.1574E-05 (1 day divided by 86,400 seconds in a day).

When you add times in Microsoft Excel, the serial number equivalents of the times are added and the result is displayed in a time format. However, only the fractional amount of the result (time less than 24 hours) can be displayed in a time format. As a result, your answer may be incorrect by a multiple of 24 hours. For example, if you add the following times
   Cell       Time     Serial equivalent (days)
   ----       -----    ------------------------

   A1         8:00     0.3333
   A2         9:00     0.375
   A3         10:00    0.4167
   A4         11:30    0.4792
              -----    ------
   Total      38:30    1.6042
the expected result is 38:30. However, the result that is displayed is 14:30. This is because only the amount to the right of the decimal point (.6042) is used by the time format. The amount to the left of the decimal point (1) is in days, and is therefore not displayed when a built-in time format is used. When formatted using the h:mm or hh:mm format, .6042 is displayed as 14:30. Follow these steps to see the expected total of "38:30":
  1. Select the cell that contains 14:30.
  2. On the Format menu, click Cells, and then click the Number tab.
  3. In the Category list, click Time. In the Type list, click 37:30:55. Click OK.
This is a proper time and can be used in other computations.


Excel X and later versions

For more information about time formats, click Excel Help on the Help menu, type time formats, click Search, and then click a topic to view it.

Excel 2001

For more information about time formats, click the Office Assistant, type formats for dates and times, click Search, and then click a topic to view it.

Note If the Assistant is hidden, click the Office Assistant button on the Standard toolbar.

Excel 98

For more information about time formats, follow these steps:
  1. On the Help menu, click Contents and Index. If you are using a version of the Macintosh operating system that is earlier than 8.0, click Contents and Index on the Balloon Help menu.
  2. In Excel Help, click Index, and then type the following text:
    time formats
  3. Click Show Topics. Click the Custom number, date, and time format codes topic, and then click Go To.
If you cannot find the information that you want, ask the Office Assistant.


Article ID: 190633 - Last Review: October 6, 2011 - Revision: 3.0
  • Microsoft Excel 2004 for Mac
  • Microsoft Excel X for Mac
  • Microsoft Excel 2001 for Mac
  • Microsoft Excel 98 for Macintosh
kbhowto KB190633

Give Feedback


Contact us for more help

Contact us for more help
Connect with Answer Desk for expert help.
Get more support from