Understanding How Excel Records Dates and Times

Excel assigns serial values to days, hours, minutes, and seconds, which makes it possible for you to perform sophisticated date and time arithmetic. The basic unit of time in Excel is the day. Each day is represented by a serial date value. The base date, represented by the serial value 1, is Sunday, January 1, 1900. When you enter a date in your worksheet, Excel records the date as a serial value that represents the number of days between the base date and the specified date. For example, Excel represents the date January 1, 2008, by the serial value 39,448, representing the number of days between the base date—January 1, 1900—and January 1, 2008.

The time of day is a decimal value that represents ...

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