Working with Excel dates is quite powerful once it is fully understood how Excel works with dates. Working with times is an extension of dates.

Excel treats a date as a serial number. Enter the number 1 in a cell. Click on the format drop down arrow and then click short date. The cell now displays 1/1/1900.

You can now see that the date serial number 1 is the equivalent of 1/1/1900. Enter the number 2 in the same cell and the display is now 1/2/1900. Enter 45100 in a cell and format it to short date and 6/23/2023 displays. You can now see that 6/23/2023 is 45100 days since 1/1/1900.

Hopefully you can see how this serial number system works. A number is entered and when date format is clicked, it’s converts the display as a real date.

For the most part, you have no need to worry about the serial number. Example: Enter 6/23/2023 in cell B10.  Excel interprets the entry and displays what you entered.  Enter 6/28/2023 in cell B11. Then, in cell D10 enter =B10-B11 and the result will be 5. You can now see how the serial number concept works. It subtracts the serial numbers that are the “real” date numbers or 5.

Hopefully, the above discussions sets the stage for working with dates, explaining how the serial number is the basis for how dates work.

Now for the good stuff:

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