WEEKDAY Function

The WEEKDAY function takes a date and returns a number between 1-7 representing the day of the week. The WEEKDAY function takes two arguments: serial_number and return_type. Serial_number should be a valid Excel date in serial number format. Return_type is an optional numeric code that controls which day of the week is considered the first day. By default, WEEKDAY returns 1 for Sunday and 7 for Saturday, as seen in the table below:

WEEKDAY supports several numbering schemes, controlled by the return_type argument. Return_type is optional and defaults to 1. The table below shows available return_type codes, the numeric result of each code, and which day is the first day in the mapping scheme.

Note: the WEEKDAY function will return a value even when the date is empty. Take care to trap this result if blank dates are possible.

Examples

By default and without a value fore return_type, WEEKDAY starts counting on Sunday:

=WEEKDAY("3-Jan-21") // Sunday, returns 1
=WEEKDAY("4-Jan-21") // Monday, returns 2

To configure WEEKDAY to start on Monday, set return_type to 2:

=WEEKDAY("3-Jan-21",2) // Sunday, returns 7
=WEEKDAY("4-Jan-21",2) // Monday, returns 1

In the example shown above, the formula in D5 (copied down) is:

=WEEKDAY(B5) // Sunday start

The formula in E5 (copied down) is:

=WEEKDAY(B5,2) // Monday start

Notes

• By default, WEEKDAY returns 1 for Sunday and 7 for Saturday.
• WEEKDAY returns a value (7) even if the date is empty.