Fence Post Spacing Calculator
Calculate the number of fence posts, spacing between posts, and total materials needed for your fencing project.
Formulas Used
Number of Spans = ⌈ Total Length ÷ Maximum Spacing ⌉ (ceiling, so no span exceeds the maximum)
Actual Spacing (c/c) = Total Length ÷ Number of Spans (evenly distributed)
Clear Opening = Actual Spacing − Post Width (converted to feet)
Line Posts = Number of Spans − 1
Total Posts = Line Posts + Corner/End Posts
Panels / Rail Sections = Number of Spans
Assumptions & References
- Post spacing is measured centre-to-centre; the clear opening subtracts one post width.
- The calculator distributes spans evenly so that no single span exceeds the specified maximum — this avoids weak long spans while minimising wasted material.
- Standard residential wood fence post spacing is 6–8 ft on centre (IRC / typical contractor practice).
- Chain-link and split-rail fences commonly use 10 ft spacing; agricultural wire fences up to 12–16 ft.
- Corner posts, gate posts, and end posts are counted separately because they require heavier setting (deeper holes, concrete) than line posts.
- Post hole depth is typically 1/3 of the above-ground post height plus 6 in for gravel drainage (not calculated here).
- Always check local building codes and HOA rules for maximum post spacing and setback requirements.
- Reference: International Residential Code (IRC); American Fence Association installation guidelines.