Using SUM In a Macro

Bob has a need to use the SUM function in a macro in order to find the sum of all the values in a column. The problem is that the number of cells to be summed will vary; for one run of the macro it could be 100 cells, while on the next it could be 300 and on the third only 25.

First, it is easy to use most worksheet functions (such as SUM) from within a macro. All you need to do is to preface the function name with "Application.WorksheetFunction." or simply "WorksheetFunction." Thus, if you know that each run of the macro will require summing A1:A100, then A1:A300, and finally A1:A25, you could use a macro like this:

Public Sub Sum_Demo()
    Dim myRange
    Dim Results
    Dim Run As Long

    For Run = 1 To 3
        Select Case Run
        Case 1
            myRange = Worksheets("Sheet1").Range("A1", "A100")
        Case 2
            myRange = Worksheets("Sheet1").Range("A1", "A300")
        Case 3
            myRange = Worksheets("Sheet1").Range("A1", "A25")
        End Select
        Results = WorksheetFunction.Sum(myRange)
        Range("B" & Run) = Results
    Next Run
End Sub

This macro uses a For . . . Next loop to specify different ranges of cells to be summed. It then uses the SUM worksheet function to assign the sum to the Results variable, which is (finally) stuffed into a cell in column B. The results of the first run are put in B1, the second in B2, and the third in B3.

While this particular macro may not be that useful, it shows several helpful techniques, such as how to define a named range, how to use the SUM function, and how to stuff the sum into a cell. What the macro doesn't do is to show how to select a variable number of cells to be summed. To do this, it is best to rely upon the End method of the Range object. The following code line shows how you can stuff the sum of the range starting at A1 and extending to just before the first blank cell in the column:

myRange = ActiveSheet.Range("A1", Range("A1").End(xlDown))
Range("B1") = WorksheetFunction.Sum(myRange)

Note that a range (myRange) is defined as beginning with A1 and extending through whatever the End method returns. This is then summed and stuffed into B1.