Fence Post Spacing and Picket Count: A Worked 100-Foot Example
October 21, 2026
For a straight fence, the number of posts is one more than the number of sections. A 100-foot fence with posts 8 feet apart has 100 ÷ 8 = 12.5, rounded up to 13 sections, which needs 14 posts. For the pickets, 100 feet is 1,200 inches; with 5.5-inch pickets and a 1/2-inch gap, each takes 6 inches, giving 200 pickets.
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Always add one: 13 sections have 14 posts because both ends need a post. Corners, gates, and ends need stronger posts, often set deeper or in concrete. A straight run that is a multiple of the spacing, such as 96 feet with 8 foot sections, would need 13 posts.
If the run does not divide evenly, shorten the spacing slightly to keep sections equal rather than leaving one short section at the end. 100 ÷ 13 = 7.69 feet between posts.
Rails and Pickets
A typical privacy fence has two rails between posts for fences up to 5 feet tall and three for taller ones. Each rail spans one section, so 13 sections × 2 rails = 26 rails.
For vertical pickets, divide the run in inches by the picket width plus gap. With no gap (board-on-board overlap or tight), 1,200 ÷ 5.5 = 218 pickets. With a 1/2-inch gap, 1,200 ÷ 6 = 200. Add 5% for culls and cuts.
| Item | Count for 100 ft | Assumptions |
|---|---|---|
| Posts | 14 | 8 ft spacing, 13 sections |
| Rails | 26 | 2 rails per section |
| Pickets | 200 (+5%) | 5.5 in wide, 1/2 in gap |
| Concrete (per post) | about 1 to 2 bags | Varies by hole size and depth |
Post Depth and Local Rules
A common guideline is to bury one third of the post length, or at least 2 feet, and deeper where frost heave is a concern. A 6-foot-tall fence often uses 8-foot posts with 2 feet in the ground.
Check local rules for height limits, setbacks from property lines, and whether you need a permit. Confirm the boundary before building, because a fence on the wrong side of the line may have to be moved.
Frequently Asked Questions
How many fence posts do I need for 100 feet?
With posts 8 feet apart, 14 posts. The rule is number of sections plus one.
How far apart should fence posts be?
Usually 6 to 8 feet on center for wood fences.
How many pickets do I need per foot?
About 2 per foot with 5.5-inch pickets and a half-inch gap.
How deep should fence posts be?
About one third of the post length in the ground, and at least 2 feet, deeper in cold climates.