Autosum vba for each new sheet added to workbook - excel

Question

My current VBA provides an sum function for pre-defined columns within worksheets which are specified and defined in the code. This works fine, however I am adding new worksheets to this workbook on a daily basis, and its therefore not feasible to edit the code everyday to add a new worksheet and range for it to sum.
Is there a way I can edit my current code in order for it to conduct the sum function for every single worksheet in the workbook? I have attached the current code for reference below.
Sub AutoSum()
Sheets("MASTER ACCOUNT REVENUE").Select
Range("D4").Select
Selection.End(xlDown).Select
ActiveCell.Offset(2, 0).Select
Dim cel1 As String, cel2 As String
cel1 = ActiveCell.Offset(-2, 0).End(xlUp).Address
cel2 = ActiveCell.Offset(-1).Address
ActiveCell.Value = "=sum(" & (cel1) & ":" & (cel2) & ")"
End Sub

Answer 1

Yes, just loop through the sheets. NOTE: It's best to avoid using .Select/.Activate
Sub autoSum_AllSheets()
Dim ws As Worksheet
Dim cel1 As String, cel2 As String
Dim firstCel As Range
For Each ws In ActiveWorkbook.Worksheets
With ws
Set firstCel = .Range("D4").End(xlDown).Offset(2, 0)
cel1 = firstCel.Offset(-2, 0).End(xlUp).Address
cel2 = firstCel.Offset(-1).Address
firstCel.Value = "=SUM(" & cel1 & ":" & cel2 & ")"
End With
Next ws
End Sub
Note: I'm aware of the redundencies in the Offset() parts, but just kept them in for OP to see how to more easily avoid .Select/.Activate.
Edit: To loop through a bunch of columns, one (albeit kludgy) way is to just add the column letters to an array:
Sub autoSum_AllSheets()
Dim ws As Worksheet
Dim cel1 As String, cel2 As String
Dim firstCel As Range
Dim cols() As Variant
cols = Array("D", "E", "F")
Dim i As Long
For Each ws In ActiveWorkbook.Worksheets
With ws
For i = LBound(cols) To UBound(cols)
Set firstCel = .Range(cols(i) & "4").End(xlDown).Offset(2, 0)
firstCel.Select
cel1 = firstCel.Offset(-2, 0).End(xlUp).Address
cel2 = firstCel.Offset(-1).Address
firstCel.Value = "=SUM(" & cel1 & ":" & cel2 & ")"
Next i
End With
Next ws
End Sub
Please note though, if the Column does not have any information in a cell after row 5, you will get an error (because the .XlDown goes to the very last row, and you can't then Offset(2,0) from there.)

Answer 2

Yes add:
Dim wscount as long
dim i as long
wscount = Activeworkbook.Worksheets.Count
for i = 1 to wscount
Sheets(i).Select
Range("D4").Select
Selection.End(xlDown).Select
ActiveCell.Offset(2, 0).Select
Dim cel1 As String, cel2 As String
cel1 = ActiveCell.Offset(-2, 0).End(xlUp).Address
cel2 = ActiveCell.Offset(-1).Address
ActiveCell.Value = "=sum(" & (cel1) & ":" & (cel2) & ")"
next i
End Sub