It's because a date in Excel is a serial number So in Windows Jan 0 1900
then every day after that gets incremented by 1. You can check that by
taking a date and format it as General, for instance today's (Nov 19th 2008)
Excel date is 39772. For Excel for Mac the dates start on Jan 1 1904 thus
the difference and since Excel for Mac came out before Excel for Windows MS
couldn't use the same date system only if they wanted to compete in
spreadsheet programs since lotus was the big shot then.

--


Regards,


Peo Sjoblom

"clinhart" wrote in message
...
Why is this happening in the first place? It wasn't happening before to
me,
then all of a sudden it started. Also, why should you have to input extra
numbers on dates, etc,, which I don't fully understand what you are saying
to
do any way, just to copy dates from one worksheet to another? Isn't there
a
"fix" for this? I am confused, and would really like to get it fixed
because
I copy dates between worksheets all the time for work. Thank you.

"Dave Peterson" wrote:

Saved from a previous post:

One workbook was using a base year of 1900 and the other was using 1904.
(tools|options|calculation tab|1904 date system)

One way to add those four years back is to find an empty cell, put 1462
into
that cell.

Copy that cell.

Select your range that contains the dates. Edit|PasteSpecial|click Add
(in the
operation box).

You may have to reformat the cell as a date (mine turned to a 5 digit
number).
But it should work.

You may want to do it against a copy...just in case.

(I'm not sure which one you'll fix. You may want to
edit|pastespecial|click
subtract.)

Most windows users use 1900 as the base date. Mac users (mostly??) use
1904 as
the base date.


Pgarbarini wrote:

I receive a file from one department and copy the information into
another
file. When I do this the date changes. It adds one day and four years
to the
date. The options has the 1904 date system selected. When I turn this
off the
dates come in correctly but the rest of my dates in the worksheet
change.
What can I do?

--

Dave Peterson