Try this
Sub test()
Dim Firstrow As Long
Dim Lastrow As Long
Firstrow = ActiveSheet.UsedRange.Cells(1).Row
Lastrow = ActiveSheet.UsedRange.Rows.Count + Firstrow - 1
Rows(Lastrow).Copy Rows(Lastrow + 1)
End Sub
Or use a function to be sure you have the last row with data
Sub test2()
Rows(LRow(ActiveSheet)).Copy Rows(LRow(ActiveSheet) + 1)
End Sub
Function LRow(sh As Worksheet)
On Error Resume Next
LRow = sh.Cells.Find(What:="*", _
After:=sh.Range("A1"), _
Lookat:=xlPart, _
LookIn:=xlFormulas, _
SearchOrder:=xlByRows, _
SearchDirection:=xlPrevious, _
MatchCase:=False).Row
On Error GoTo 0
End Function