Think in sections
A fence is sections between posts. At 8-foot spacing, a 100-foot run is 13 sections (rounded up) and 14 posts. That single number — sections — drives almost everything: rails multiply by section, posts come from section plus one, and concrete comes from posts.
The four-line takeoff
- Posts: sections + 1, plus corner and gate-post upgrades.
- Pickets: run length in inches ÷ (picket width + gap). A 5.5-inch picket at a 0.5-inch gap runs 2 pickets per foot.
- Rails: sections × spacing × rails per section (2–3 by height and style).
- Concrete: about two 50 lb bags per post — roughly one cubic foot per hole.
The edge cases are the estimate
Gates are hardware and framing, not pickets. Corners add posts. Slopes change labor and sometimes design. Soil type changes digging hours more than any material line. Walk the line, count the exceptions, and put them in writing — the straight sections take care of themselves.