Dynamic rolling previous N months

Hi YO_CO ,

Here is my sample data:

I don't know how your calculated Calendar column is created, so I use this instead:

Then I create a parameter for choose month numbers:

Use this DAX to create a measure and put the measure into the matrix visual:

SUM_VALUE = 
VAR _Parameter = SELECTEDVALUE(Parameter[Parameter])
VAR _CurrentMonth = MAX('Table'[Date])
VAR _PreviousMonth = EOMONTH(_CurrentMonth, -_Parameter)
RETURN
CALCULATE(
    SUM('Table'[Value]),
    ALL('Table'),
    'Table'[Date] > _PreviousMonth && 'Table'[Date] <= _CurrentMonth
)

Then use this DAX to create another measure as a filter:

Measure = 
VAR _Parameter = SELECTEDVALUE(Parameter[Parameter])
VAR _CurrentMonth = MAXX(FILTER(ALL('Table'), 'Table'[Flag] = "IsCurrentMonth"), 'Table'[Date])
VAR _PreviousMonth = EOMONTH(_CurrentMonth, -_Parameter)
RETURN
IF(
    MAX('Table'[Date]) > _PreviousMonth && MAX('Table'[Date]) <= _CurrentMonth,
    1,
    0
)

Make the settings as shown in the figure below:

Output:
If I choose 3 months:

If I choose 13 months:

Best Regards,
Dino Tao
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.