Comments on: Converting Excel date/time to Unix timestamp http://blog.webconsultingengineering.com/phptalk/timestamp-excel2unix.html In search of reasons for web addiction Fri, 03 Sep 2010 09:21:06 +0000 hourly 1 http://wordpress.org/?v=3.0.1 By: Susenjit http://blog.webconsultingengineering.com/phptalk/timestamp-excel2unix.html/comment-page-1#comment-398 Susenjit Fri, 03 Sep 2010 09:21:06 +0000 http://blog.webconsultingengineering.com/?p=12#comment-398 Thanks for checking. However I used this formula to convert Excel date to Unix timestamp. I had written a program which picks up a cell(containing a date) value and then convert it in Unix timestamp. I found the result was correct. After getting your post I just made another test. You can check it yourself. Put 1/1/1970 and 1/1/1900 in 2 cells now change the format of these cells as number. What you will get is that first cell value as 25569 and second cell value as 1. But while calculating the day difference you should consider 1/1/1900 as day 0. However using $DayDifference as 25568 I converted a Excel date to Unix timestamp and print that using strftime(). I got one day more rather than the expected result. Thanks for checking. However I used this formula to convert Excel date to Unix timestamp. I had written a program which picks up a cell(containing a date) value and then convert it in Unix timestamp. I found the result was correct.

After getting your post I just made another test. You can check it yourself. Put 1/1/1970 and 1/1/1900 in 2 cells now change the format of these cells as number. What you will get is that first cell value as 25569 and second cell value as 1. But while calculating the day difference you should consider 1/1/1900 as day 0.

However using $DayDifference as 25568 I converted a Excel date to Unix timestamp and print that using strftime(). I got one day more rather than the expected result.

]]> By: Smitty http://blog.webconsultingengineering.com/phptalk/timestamp-excel2unix.html/comment-page-1#comment-397 Smitty Thu, 02 Sep 2010 11:49:25 +0000 http://blog.webconsultingengineering.com/?p=12#comment-397 Thank you for this article! It has greatly simplified a data import for me today. I dropped this in to my spreadsheet and then converted one of the Unix timestamps back into a date (using http://www.unixtimestamp.com/) but the date was off by one day. Just to double-check the math, I entered a formula in a cell to find the difference between 1/1/1970 and 1/1/1900. The result? 25568--one less than the $DayDifference you specify above. Making that one change resulted in a Unix timestamp that, when converted back to mm/dd/yyyy matched the original. Thank you for this article! It has greatly simplified a data import for me today.

I dropped this in to my spreadsheet and then converted one of the Unix timestamps back into a date (using http://www.unixtimestamp.com/) but the date was off by one day. Just to double-check the math, I entered a formula in a cell to find the difference between 1/1/1970 and 1/1/1900. The result? 25568–one less than the $DayDifference you specify above.

Making that one change resulted in a Unix timestamp that, when converted back to mm/dd/yyyy matched the original.

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