How Many Pickets for a 100-Foot Fence?
A 100 ft fence is a common residential project. Here is the picket count, and how spacing, posts and rails change the material list.
A 100 ft fence is a common residential project, and the picket count is the number most people want first. But a fence is a system: posts, rails, pickets and post-hole concrete all scale with the length, and each has its own spacing rule.
The picket count
Picket count depends on the fence length and the center-to-center spacing. At 5.5 in wide pickets with a 0.5 in gap, the spacing is 6 in, or 0.5 ft. A 100 ft fence then needs about 200 pickets. Wider spacing reduces the count but weakens the fence; tighter spacing increases privacy and material.
Posts
Posts are typically spaced 6 to 8 ft apart. A 100 ft fence needs about 14 to 17 posts, including the end and corner posts. Post count is independent of picket spacing, which is why the two must be calculated separately.
Rails
A standard fence has two or three horizontal rails per section. Rail count is posts minus one, times the number of rails per section. For a 100 ft fence with 15 posts and three rails, that is 42 rails.
Post-hole concrete
Each post hole typically needs about 0.5 to 1.0 ft³ of concrete. For 15 posts, that is 8 to 15 ft³, or roughly 0.3 to 0.6 cubic yards, which is usually done with bagged mix. Use the fence calculator to size the concrete and the bag count.
Ordering advice
Order pickets, posts and rails by the piece, with a waste allowance of 5 % to 10 %. Buy posts and rails from the same treatment level and species. Add one or two extra pickets and a post for defects. And remember that a quantity estimate is not a structural design: post depth, concrete and local wind loads are separate decisions.