Custom month start and end date dax

Anonymous ,

I'm assuming your first column is a date table. Try this formula as it should similarly work for all three expressions (with minor tweaks):

Last (n) Range = 

VAR _CurrDate = MAX('Table'[Date])
VAR _MonthNum = MONTH(_CurrDate)

VAR _Offset = 3 // how many months to show. 1 equals last month, 2 equals last 2 months, 3 equals last 3 months, etc.

VAR _StartDate = 
    IF( _MonthNum = 1, 
        DATE(YEAR(_CurrDate), 1 * _Offset, 1), 
        DATE(YEAR(_CurrDate), MONTH(_CurrDate) - (1 * _Offset), 26)
    )

VAR _EndDate = 
    SWITCH( 
        _MonthNum, 
        1, DATE(YEAR(_CurrDate), 1, 25), 
        12, DATE(YEAR(_CurrDate), 12, 31), 
        DATE(YEAR(_CurrDate), MONTH(_CurrDate), 25)
    )

RETURN

_StartDate & " - " & _EndDate

Simple enough, add a calculated column in relation to "Production Year-Month" to the calendar table,