Excel supports two date systems: the 1900 and 1904 date systems. The default date system for Microsoft Excel for Windows is 1900. The default date system for Microsoft Excel for the Macintosh is 1904. You can change the date system. On the Tools menu, click Options, click the Calculation tab, and then select or clear the 1904 date system check box.
The date system is changed automatically when you open a document from another platform. For example, if you are working in Excel for Windows and you open a document created in Excel for the Macintosh, the 1904 date system check box is selected automatically.The following table shows the first date and the last date for each date system and the serial value associated with each date.
| Date system | First date | Last date |
|---|---|---|
| 1900 | January 1, 1900 (serial value 1) |
December 31, 9999 (serial value 2958465) |
| 1904 | January 2, 1904 (serial value 1) |
December 31, 9999 (serial value 2957003) |
How Excel interprets two-digit years
To ensure that year values are interpreted as you intended, type year values as four digits (2001, rather than 01). By entering four digits for the years, Excel won't interpret the century for you.
For Microsoft Windows 2000 or later
If you are using Microsoft Windows 2000 or later, the Regional Options in Windows Control Panel controls how Excel interprets two-digit years.
For dates entered as text values
When you enter a date as a text value, Excel interprets the year as follows:
- 00 through 29 Excel interprets the two-digit year values 00 through 29 as the years 2000 through 2029. For example, if you type the date 5/28/19, Excel assumes the date is May 28, 2019.
- 30 through 99 Excel interprets the two-digit year values 30 through 99 as the years 1930 through 1999. For example, if you type the date 5/28/98, Excel assumes the date is May 28, 1998.