Wood Fence Calculator
Calculates wood privacy fencing (dog-ear, flat-top, shadowbox) including 4x4 pressure-treated posts, 2x4 horizontal runner rails (2 or 3 rails), vertical 1x6 pickets, and gate framing kits.
Formula
Posts = Ceil(Linear Ft ÷ 8) + 1 + Gates; Rails = (Posts - 1) × 3; Pickets = Linear Ft × Pickets/Ft × (1 + Waste %)
1. Post Count = Ceil(Linear Ft ÷ 8 ft post spacing) + 1 + Gate Count 2. Rail Count (2x4 × 8-ft) = (Post Count - 1) × (Height >= 6 ? 3 rails : 2 rails) 3. Pickets per Foot: Solid = 2.18; Shadowbox = 3.10; Spaced = 2.40 4. Total Pickets with Waste = Ceil(Linear Ft × Pickets/Ft × (1 + Waste %)) 5. Concrete Bags (50 lb fast-set) = Post Count × 2 bags per post
Inputs
- Total Fence Length
- Fence Height
- Picket Style & Spacing
- Number of Walk Gates
Worked example
Building a 150-ft wood privacy fence with 4x4 posts on 8-ft centers, 3 rails, and 1 walk gate.
Outcome: Posts: 150 ÷ 8 = 18.75 -> 20 line posts + 1 gate post = 21 posts (4x4 × 8-ft). Rails: 20 sections × 3 rails = 60 rails (2x4 × 8-ft). Pickets: 150 × 2.18 = 327 pickets (360 pickets with 10% waste). Concrete: 42 bags (50 lb fast-setting).
Should fence posts be set in concrete or packed gravel?
In most residential soils, setting 4x4 posts in 2 bags of concrete provides superior lateral wind resistance. Crown the top of the concrete above ground level so rainwater slopes away from the wood post.