Your Kit comes with one Start post, one Stop (or end) post and two corner posts. If you use one side of your house to complete the fence (so essentially you are purchasing 3 sides for your fence – not 4), you will not have order anything extra. This is common and is default selection is perfect for 95% of customers. If you are creating an advanced layout (for example, a free standing enclosure) then you will need order 2 extra corner posts.