Changing Excel's Starting Date

Excel allows you to choose which arbitrary date you use as the beginning point for serial numbers. In the PC world, this date is January 1, 1900. If you are working with Excel workbooks imported from the Macintosh environment, however, you will want to set the starting date to January 2, 1904—the date used on the Mac.

To set which of these two dates is used, follow these steps if you are using a version of Excel prior to Excel 2007:

1. Choose Options from the Tools menu. Excel displays the Options dialog box.
2. Make sure the Calculation tab is selected. (Click here to see a related figure.)
3. The 1904 Date System check box controls which dating system is used. If the check box is not selected, then the January 1, 1900 starting date is used; if it is selected, then January 2, 1904 is used.

If you are using Excel 2007 then you should follow these steps:

1. Click the Office button and then click Excel Options. Excel displays the Excel Options dialog box.
2. Click Advanced at the left of the dialog box.
3. Scroll through the available options until you see the section titled When Calculating this Workbook. (Click here to see a related figure.)
4. The Use 1904 Date System check box controls which dating system is used. If the check box is not selected, then the January 1, 1900 starting date is used; if it is selected, then January 2, 1904 is used.