Once you decide the default Auto Date table isn’t adequate, you can create one that fulfills your grouping and filtering requirements.

You can enter data into a Microsoft Excel sheet or run a bit of M code in Microsoft Excel Power Query when you need to create a table.

How Date and Time Serial Numbers Are Generated in Excel The serial numbers for dates in all modern versions of Microsoft Excel start at 1 for January 1, 1900, increasing with each subsequent day.