Posts and panels for a fence run.
Posts = (fence length ÷ post spacing) + 1 corner post. Panels = fence length ÷ post spacing.
8 ft spacing is common for privacy fences; 6 ft for chain link.
Post spacing is a structural decision, not just a material-quantity one — closer spacing adds strength and wind resistance but increases both post count and labor, which is why it varies by fence type and local wind conditions.
100 ft fence at 8 ft spacing: 14 posts (13 spans + 1 end + 1 buffer), 13 panels.
Yes — heavier duty for gates. Budget separately.
1/3 of post height below grade, in concrete. For a 6 ft fence, that's a 2–3 ft hole.
Yes — a survey or clear property line confirmation is worth doing first, since a fence built even slightly over a boundary can create real disputes with neighbors later.