Comments on: Excel Date Weirdness http://compoundthinking.com/blog/index.php/2006/01/20/excel-date-wierdness/ Thinking about programming in new ways Tue, 15 Mar 2011 02:30:01 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: Paul http://compoundthinking.com/blog/index.php/2006/01/20/excel-date-wierdness/#comment-233566 Paul Mon, 01 Sep 2008 23:38:53 +0000 http://compoundthinking.com/blog/?p=66#comment-233566 This is all great as far as it goes, and I've a problem. I am trying to copy data from an Excel document written in Excel for windows into an Excel for Mac doc. Either the 1904 box is clicked and my Windows data is off or the box isn't clicked and my Mac data is off. I figure there is a way to use the number 1462 (days difference between the two basis dates) but senility seems to be taking hold of my brain. Any ideas folks? This is all great as far as it goes, and I’ve a problem. I am trying to copy data from an Excel document written in Excel for windows into an Excel for Mac doc. Either the 1904 box is clicked and my Windows data is off or the box isn’t clicked and my Mac data is off. I figure there is a way to use the number 1462 (days difference between the two basis dates) but senility seems to be taking hold of my brain. Any ideas folks?

]]> By: Jay http://compoundthinking.com/blog/index.php/2006/01/20/excel-date-wierdness/#comment-153413 Jay Thu, 10 Apr 2008 20:20:43 +0000 http://compoundthinking.com/blog/?p=66#comment-153413 To fix this in Excel '07: office button, excel options, advanced tab, scroll down to "when calculating this workbook". This has the 1904 / 1900 checkbox. To fix this in Excel ’07: office button, excel options, advanced tab, scroll down to “when calculating this workbook”. This has the 1904 / 1900 checkbox.

]]> By: Mark Amanns http://compoundthinking.com/blog/index.php/2006/01/20/excel-date-wierdness/#comment-135663 Mark Amanns Thu, 28 Feb 2008 01:36:47 +0000 http://compoundthinking.com/blog/?p=66#comment-135663 I encountered this bug too, but in automated web submissions. So my priority is simply to identify the spreadsheets that have the date set to 1904 and handle accordingly, either to reject and request the user change their Excel date setting or process knowing how to adjust the dates by code offsets. I haven't yet found a site that describes where in the Excel file that flag is saved, but for Excel 2003 it appears to be in byte 765. Whether that applies to spreadsheets in other Excel versions, I could only guess. I encountered this bug too, but in automated web submissions. So my priority is simply to identify the spreadsheets that have the date set to 1904 and handle accordingly, either to reject and request the user change their Excel date setting or process knowing how to adjust the dates by code offsets. I haven’t yet found a site that describes where in the Excel file that flag is saved, but for Excel 2003 it appears to be in byte 765. Whether that applies to spreadsheets in other Excel versions, I could only guess.

]]> By: tech.knwldg.net » excel mode-1904 http://compoundthinking.com/blog/index.php/2006/01/20/excel-date-wierdness/#comment-122450 tech.knwldg.net » excel mode-1904 Thu, 17 Jan 2008 22:41:56 +0000 http://compoundthinking.com/blog/?p=66#comment-122450 [...] Excel was first developped on a Macintosh, the Internet tells.  And to make it run more swiftly, developers added a special tweak to the way it handles [...] [...] Excel was first developped on a Macintosh, the Internet tells.  And to make it run more swiftly, developers added a special tweak to the way it handles [...]

]]> By: mr fixit http://compoundthinking.com/blog/index.php/2006/01/20/excel-date-wierdness/#comment-114944 mr fixit Mon, 10 Dec 2007 12:22:02 +0000 http://compoundthinking.com/blog/?p=66#comment-114944 to fix the date when importing into Excel from Mac, in Excel just go to tools/options/calculation and click 1904 date system OK to fix the date when importing into Excel from Mac, in Excel just go to tools/options/calculation and click 1904 date system OK

]]> By: Jabber http://compoundthinking.com/blog/index.php/2006/01/20/excel-date-wierdness/#comment-28033 Jabber Thu, 15 Feb 2007 20:37:12 +0000 http://compoundthinking.com/blog/?p=66#comment-28033 Mac Fix from the Help menu: Change the date system between 1900 and 1904 1. On the Excel menu, click Preferences, and then click Calculation. 2. Do one of the following in the 1904 date system check box: • To use the Macintosh standard system (1904), select the check box. • To use the Windows standard system (1900), clear the check box Mac Fix from the Help menu:
Change the date system between 1900 and 1904
1. On the Excel menu, click Preferences, and then click Calculation.
2. Do one of the following in the 1904 date system check box:
• To use the Macintosh standard system (1904), select the check box.
• To use the Windows standard system (1900), clear the check box

]]> By: Mark Ramm http://compoundthinking.com/blog/index.php/2006/01/20/excel-date-wierdness/#comment-2826 Mark Ramm Sun, 13 Aug 2006 02:03:37 +0000 http://compoundthinking.com/blog/?p=66#comment-2826 Paula, The problem you describe seems quite different than the one above, and it is actually something that you can fix yourself pretty easily. 1) Highlight the cell that should have a date, 2) go to the format menu, 3) click cells, 4) chang the format to Date. Paula,

The problem you describe seems quite different than the one above, and it is actually something that you can fix yourself pretty easily.

1) Highlight the cell that should have a date,
2) go to the format menu,
3) click cells,
4) chang the format to Date.

]]> By: Paula Morgan http://compoundthinking.com/blog/index.php/2006/01/20/excel-date-wierdness/#comment-2817 Paula Morgan Sat, 12 Aug 2006 22:48:28 +0000 http://compoundthinking.com/blog/?p=66#comment-2817 HI, So how does one fix the date problem presentation in Excel? The formula window displays the date format selected, but the cell shows the gibberish numeric sequence! MS wants to charge $35 just to report the problem to them. Doesn't MS ever take responsibility to fix problems? Thanks, Paula HI,
So how does one fix the date problem presentation in Excel?
The formula window displays the date format selected, but the cell shows the gibberish numeric sequence!

MS wants to charge $35 just to report the problem to them.
Doesn’t MS ever take responsibility to fix problems?
Thanks, Paula

]]> By: Mark Ramm http://compoundthinking.com/blog/index.php/2006/01/20/excel-date-wierdness/#comment-150 Mark Ramm Wed, 15 Feb 2006 12:15:34 +0000 http://compoundthinking.com/blog/?p=66#comment-150 Thanks for the background info on the design decision by Apple to start counting from 1904. I can understand Apple's reasoning here, even though it turns out to have been less than optimal for compatibility with the future. But the Microsoft's design decision that it would be worth their time to maintain two different date systems in excel -- for 15+ years! and 10+ product releases -- seems a bit absurd. Thanks for the background info on the design decision by Apple to start counting from 1904. I can understand Apple’s reasoning here, even though it turns out to have been less than optimal for compatibility with the future. But the Microsoft’s design decision that it would be worth their time to maintain two different date systems in excel — for 15+ years! and 10+ product releases — seems a bit absurd.

]]> By: oefe http://compoundthinking.com/blog/index.php/2006/01/20/excel-date-wierdness/#comment-120 oefe Sat, 11 Feb 2006 19:11:54 +0000 http://compoundthinking.com/blog/?p=66#comment-120 Well, not actually a bug but an odd design decision in MacOS, actually over 20 years ago: The time functions in MacOS returned time as seconds since January 1, 1904, and Excel (originally created on the Mac) used this system initially. Why 1904? Because 1900, although divisibly by 4, wasn't a leap year. By using 1904 as a base, they saved a few bytes code, and every byte counted when they tried to squeeze the entire MacOS into 64KiB of ROM... For the PC version of Excel, Microsoft decided that it would be better to use a more "conventional" base, i.e. 1900. But they didn't handle this leap year issue correctly, hence it is off by one day. Even later, they added this option to enable compatibility between Excel sheets between created on PC and Mac... Well, not actually a bug but an odd design decision in MacOS, actually over 20 years ago: The time functions in MacOS returned time as seconds since January 1, 1904, and Excel (originally created on the Mac) used this system initially.

Why 1904? Because 1900, although divisibly by 4, wasn’t a leap year. By using 1904 as a base, they saved a few bytes code, and every byte counted when they tried to squeeze the entire MacOS into 64KiB of ROM…

For the PC version of Excel, Microsoft decided that it would be better to use a more “conventional” base, i.e. 1900. But they didn’t handle this leap year issue correctly, hence it is off by one day.

Even later, they added this option to enable compatibility between Excel sheets between created on PC and Mac…

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