NWM returns the Number of Weeks in a Month.
MonthOffset/Date: If a number it is the Zero based offset from the Start Date of the report. If this field is a date string (i.e. "07/16/2004") or refers to a cell with a date in it, it sets the month to calculate for
0 = Current month
1 = One month after current month
2 = Two months after current month
WeekDef: Defines the week. IE W7 is Sunday thru Saturday. Click here for a table defining weeks and the corresponding values for n.
Start Date of report is March 1st, 2021
=NWM(1,"W7") - Returns 4 as March 2021 has four (4) Sun-Sat Weeks.