How the fence panel calculator works
The layout math
Panels = run ÷ panel width, and the remainder is the honest part: a 300 ft run of 6 ft panels is 50 panels exactly — but 310 ft is 51 panels plus a 4-foot odd bay you fill with a cut panel or an adjusted post spacing. Professional layouts either cut the last panel or redistribute: shrink every bay slightly (310 ÷ 51 = 6.08 ft spacing) to keep widths uniform. Both are legitimate; the calculator shows the numbers for your call.
Post logic
Posts sit at every panel joint plus both ends and both gate jambs: posts = panels + 1 + gates × 1 roughly (gate posts replace panel posts at gate locations). Corner posts count once for two directions. The 10% waste margin covers slope cuts, damaged pickets, and the one panel installed backwards.
Before layout: the line itself
Call 811 (free utility locate), confirm the boundary with your plat — fences installed "where the old one was" inherit old fences' mistakes — and check municipal height limits (commonly 4 ft front / 6 ft side-rear) and corner-visibility rules. An afternoon of paperwork prevents the fence-and-lawyer special.