Excel WEEKDAY function

Function              WEEKDAY

Description       Excel WEEKDAY function takes input of a date and returns a number between 1 to 7 representing the day of week. By default, WEEKDAY returns 1 for Sunday and 7 for Saturday.

Syntax  WEEKDAY(serial_number, [return_type])

serial_number – The date for which you want to get the day of week.

return_type – [optional] A number 1-3 representing day of week mapping scheme. Default is 1.

Return_type	Number returned
1 or omitted	Numbers 1 (Sunday) through 7 (Saturday). Behaves like previous versions of Microsoft Excel.
2	Numbers 1 (Monday) through 7 (Sunday).
3	Numbers 0 (Monday) through 6 (Sunday).
11	Numbers 1 (Monday) through 7 (Sunday).
12	Numbers 1 (Tuesday) through 7 (Monday).
13	Numbers 1 (Wednesday) through 7 (Tuesday).
14	Numbers 1 (Thursday) through 7 (Wednesday).
15	Numbers 1 (Friday) through 7 (Thursday).
16	Numbers 1 (Saturday) through 7 (Friday).
17	Numbers 1 (Sunday) through 7 (Saturday).

Example: