How Many Fence Posts Do I Need?
Divide your fence's length by your post spacing (8 ft on-center is standard), round up to a whole section, then add one — a fence always needs one more post than it has sections. That covers a single straight run; for corners, gates, or a different picket size, the fence calculator handles those directly. This page is a quick reference table by fence length, plus a worked example for a fence with a corner.
Posts, rails, and pickets by fence length
Figures below assume 8 ft post spacing, a tall (6 ft+) privacy fence at 3 rails per section, and standard 5.5in pickets with a 0.25in gap.
| Fence length | Posts | Rails | Pickets |
|---|---|---|---|
| 50 ft | 8 | 21 | 105 |
| 100 ft | 14 | 39 | 209 |
| 150 ft | 20 | 57 | 314 |
| 200 ft | 26 | 75 | 418 |
Post spacing default (8 ft on-center): This Old House, "How to Build a Fence" — a shorter fence (up to about 4 ft) needs fewer rails per section, which changes the rail column but not posts or pickets; the calculator switches height categories directly.
A full example: an L-shaped fence with one corner
This calculator models one straight run, and a corner means two runs sharing one post — a common source of over-ordering if you calculate each run in isolation and simply add the results. Take an L-shaped yard fence: a 60 ft run and a 40 ft run meeting at one corner, both tall privacy height. The 60 ft run needs 60 ÷ 8 = 7.5, rounded up to 8 sections, or 9 posts; 8 sections × 3 rails = 24 rails; and 60 ft = 720 in ÷ 5.75in per picket unit ≈ 125.2, rounded up to 126 pickets. The 40 ft run needs 40 ÷ 8 = 5 sections exactly, or 6 posts; 5 × 3 = 15 rails; and 40 ft = 480 in ÷ 5.75in ≈ 83.5, rounded up to 84 pickets. Adding the two runs separately gives 9 + 6 = 15 posts — but the corner post is shared between both runs, not built twice, so the real total is 14 posts, along with 24 + 15 = 39 rails and 126 + 84 = 210 pickets. Missing that one-post correction is a small error on a two-run fence, but it compounds on a yard with three or four corners.