Change excel file in batch

ALimiti 

If you need to change only a few formulas, you could use the following macro as starting point. You'll have to modify it for your situation of course.

Sub UpdateFormulas()
    Dim fld As String
    Dim fil As String
    Dim wbk As Workbook
    Dim wsh As Worksheet
    Application.ScreenUpdating = False
    ' Folder path with trailing backslash
    fld = "C:\Excel\"
    ' First filename
    fil = Dir(fld & "*.xls*")
    ' Loop through the files
    Do While fil <> ""
        ' Open workbook
        Set wbk = Workbooks.Open(Filename:=fld & fil)
        ' Refer to a sheet
        Set wsh = wbk.Worksheets(1)
        ' Change a formula
        wsh.Range("A20").Formula = "=SUM(A1:A19)"
        ' Save and close the workbook
        wbk.Close SaveChanges:=True
        ' Get next filename
        fil = Dir
    Loop
    Application.ScreenUpdating = True
End Sub

If you need to change a large number of formulas, I'd prepare a worksheet with cell or range addresses in the first column, and the new formulas (as text) in the second column.

It would then be possible to use this in an expanded version of the above macro.