All functions / Date & Time
WEEKDAY
The day of the week as a number.
Syntax
=WEEKDAY(serial_number, [return_type])
Arguments
serial_number: A date (or a cell containing one).return_type(optional): 1 (default): Sunday=1…Saturday=7. 2: Monday=1…Sunday=7. 3: Monday=0…Sunday=6.
Example
=WEEKDAY(A2, 2) → 1 for a Monday