Event code can do this.
Enter a 0 in C1 then copy/paste this code into your worksheet module.
Private Sub Worksheet_Change(ByVal Target As Range)
If Intersect(Target, Me.Range("A1")) Is Nothing Then Exit Sub
On Error GoTo enditall
Application.EnableEvents = False
If Target.Value <> "" Then
With Target.Offset(0, 2)
.Value = .Value + 1
End With
End If
enditall:
Application.EnableEvents = False
End Sub
Right-click on the sheet tab and "View Code"
Paste into that sheet module.
Whe you change A1 C1 will add to the count each time.
Gord Dibben MS Excel MVP