Sub esv()
Dim x As Variant, r As Long, c As Long
Application.ScreenUpdating = False
x = Range("c4", Cells(Rows.Count, "c").End(xlUp))
For r = 1 To UBound(x, 1)
For c = 1 To UBound(x, 2)
x(r, c) = Replace(x(r, c), ",", ".")
Next c: Next r
Range("c4", Cells(Rows.Count, "c").End(xlUp)) = x
End Sub