Problem with Excel Dates

[ewize1]

Do you know that there is no 29 Feb 1900? However, Excel allows you to enter 29 Feb 1900 into a cell without any error. The calendar in Outlook is alright.

I discovered this when I was doing some calculations and found that my result is errorneous. I happened to use 31 Jan 1900 as my reference date, thus 1 Mar 1900 became 30 days after 31 Jan 1900 instead of 29. I guess the simpliest fix to this problem is to change the reference date to one that falls after 29 Feb 1900. Can I use the Outlook calendar in Excel?

Is this a bug in Excel, which I suppose it should be? I'm using Excel 2003, is there someone who is using the latest version? Maybe you can try to verify this.

Regards.

 

[Doug.T]

That is why Mac's use the 1904 date system, to avoid problems with 1900 not being a leap year.

 

[Doug.T]

Blame Lotus.

http://www.cpearson.com/excel/datetime.htm

"Actually, this number is one greater than the actual number of days. This is because Excel behaves as if the date 1900-Feb-29 existed. It did not. The year 1900 was not a leap year (the year 2000 is a leap year). In Excel, the day after 1900-Feb-28 is 1900-Feb-29. In reality, the day after 1900-Feb-28 was 1900-Mar-1 . This is not a "bug". Indeed, it is by design. Excel works this way because it was truly a bug in Lotus 123. When Excel was introduced, 123 has nearly the entire market for spreadsheet software. Microsoft decided to continue Lotus' bug, in order to fully compatible. Users who switched from 123 to Excel would not have to make any changes to their data. As long as all your dates later than 1900-Mar-1, this should be of no concern. "