Hello. (thank you in advance for your time)
I have two columns in this format: "dd/mm/yyyy - hh:mm". They are recognized in excel as a general format. I need to calculate the difference between dates but a #value error appears when that is tried.

I tried using a personalized format "dd/mm/yyyy - hh:mm" for the columns, but excel does not recognize the format and the error persists.

If I separate date and time using text to columns, the date format is recognized and differences can be calculated between dates. There is no such luck with the time format. Difference between times in hh:mm format still results in #value error.

How can I get excel to recognize the format in the entire columns so I can calculate diferences between date and time, and have the result in hours? (I am trying to calcuate exact time between entrance and exit. One colum has entrance date and time, other has exit date and time.)

Hi Ricardo,

Have you tried an If formula?

Column 1   Column 2   Sum
5/22/13 23:10   7/25/13 20:45   63.90 Formula =SUM(B2-A2) with A2 being column 1 and B2 being column 2

Give this a try to see if it works for you.  Remember that the - is an operation in Excel.  You may want to change the way you display the general format (i.e., dd/mm/yyyy hh:mm not dd/mm/yyyy - hh:mm)

Hope this works or you.

Mary Lindsey
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Mary A. Lindsey


I can answer Microsoft Excel 2000-2007 questions regarding formatting, styles, shortcut keys, templates, forms, etc, but will not answer any macro questions.


I have over 15 years experience working in corporate America as legal and financial document support specialist. I have designed a template that converts html and Excel files to inserts these numerical data into Word documents so that there will be no document corruption because of file size and graphics that comes as part of HTML and Excel.


I am a Microsoft Office Master Instructor (MOS), Certiport Administrator and Proctor (97-2003)

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