Getting the formula in this For loop to include the current column(colnum)

[chazrab]

This code

Dim X As Range
   Sheets("Budget").Select
      For i = colnum + 1 To 54
      Cells(30, i).Value = Cells(30, i - 1).Value - Cells(18, i).Value 
      If Cells(30, i) = 0 Then
         MsgBox "Balance is 0 at col  " & i & "  " & "  and week  " & Cells(2, i)
         Range(Cells(30, i + 1), Cells(30, 54)).ClearContents
         Exit For
      End If                                                           
     Next
     End Sub

works perfectly for every column AFTER colnum. When I change this line

 For i = colnum + 1 To 54

to

 For i = colnum  To 54

the calculation

 Cells(30, i).Value = Cells(30, i - 1).Value - Cells(18, i).Value

does not calculate correctly. It is something very simple I haven't been able to figure out yet.
That is, to use For i = colnum To 54 and have the formula calculate the correct balances on the current (colnum) and each successive cell column.
It's been a struggle. Can anyone help me with the correct formula that will include colnum
and not start the For loop at colnum +1 to have it come out right ?

Tried to keep it simple, but complete.

Thanks for anyone's help.
cr

 

[Michael M]

You haven't declared colnum ?
AND what is colnum set to in the first instance ?

 

[chazrab]

You haven't declared colnum ?
AND what is colnum set to in the first instance ?

Colnum is a function in a module that varies with time. This should be self explanatory:

Function colnum()
colnum = Round((Date - DateValue("12/19/2018")) / 7, 0)
'MsgBox colnum
End Function

Very simply, as weeks change throughout the year, so does the value of colnum. To me, this has nothing to do with my
issue - the problem is in the calculation in the For loop formula I created.
cr