Excel Macro - Set and autofill a range?

Hello,



I recorded a macro for excel and part of the code is to create an index column that fills the cell with a row count (i.e. A2=1, A3=2, etc.) based on the data in Column B). The macro recorded and worked perfectly, however when I try to use it on another file, the macro runs into a problem because each file doesn't have the same amount of filled rows to count. How can I modify the code below to adjust to any excel file I open regardless of how many rows of data there are?


Columns("A:A").Select
Selection.Insert Shift:=xlToRight, CopyOrigin:=xlFormatFromLeftOrAbove
Range("A1").Select
ActiveCell.FormulaR1C1 = "Index"
Columns("B:B").Select
Selection.Copy
Columns("A:A").Select
Selection.PasteSpecial Paste:=xlPasteFormats, Operation:=xlNone, _
SkipBlanks:=False, Transpose:=False
Application.CutCopyMode = False
Range("A2").Select
ActiveCell.FormulaR1C1 = "1"
Range("A3").Select
ActiveCell.FormulaR1C1 = "2"
Range("A2:A3").Select
Selection.AutoFill Destination:=Range("A2:A295324")
Range("A2:A295324").Select