dax percent of month complete
percentage of completion of the month =
CALCULATE (
DIVIDE ( DAY ( TODAY () ), DAY ( LASTDATE ( 'Date'[Date] ) ), 0 ),
FILTER (
ALL ( 'Date' ),
YEAR ( 'Date'[Date] ) = YEAR ( TODAY () )
&& MONTH ( 'Date'[Date] ) = MONTH ( TODAY () )
)
)