Dates and time are treated as serial numbers or integer values
Dates and times are stored in excel as integers or serial numbers. The whole idea of integer representation dates back to the 1st of January 1900, and this is the point in which Excel starts counting. Thus, the number 1, by default, represents January 1, 1900. If we stick to this calculation, a number like 23 will be treated as the 23rd of January 1900 and so on. Regardless of the format, the date and time will be the same no matter what.
