You have a long MS Excel list. You want to find the last row for further calculations in your code.

Resolution

Sub Last_Row()
'Declare your variables
Dim I As Integer, RStart As Integer, CStart As String
'Get your list ID Column
CStart = InputBox("Please enter the column letter your unique ID is in", "Column Start", "A")
'Get your list Start Row
RStart = InputBox("Please enter the row number your list starts in", "Row Start", 0)
'Select the first cell of your column
Set c = Range(CStart & RStart)
'Cycle through your data list
Do While Not IsEmpty(c)
Set c = c.Offset(1, 0)
Loop
'Set the last row to a variable for later use
I = c.Offset(-1, 0).Row

End Sub