Panel Fence Post and Panel Calculator

How many panels and posts does a panel fence need?

First the gate openings are deducted from the total line length to get the fence length. The number of panels is the fence length divided by the post spacing, rounded up: panels = ⌈fence length / post spacing⌉. The last panel is usually cut, and the calculator gives its width.

Why are there more posts than panels?

On a straight line every panel has a post at each end and neighbouring panels share a post. So 4 panels need 5 posts. Each gate splits the fence into two runs and adds one more post. On a closed boundary the last panel fixes to the first post, so with no gate the post count equals the panel count.

• Open line: posts = panels + gates + 1
• Closed boundary: posts = panels + gates

Footing concrete

A cylindrical hole is assumed for each post: V = π / 4 × diameter² × depth. The total is multiplied by the number of posts.

Example

An open line of 100 m with one 4 m gate has 96 m of fence. At 2.5 m spacing you need 39 panels and the last one is cut to 1 m. The post count is 41. With footings 30 cm in diameter and 50 cm deep, about 1.45 m³ of concrete is needed.

Limits

The calculation works on total length. On plots with corners, calculating each straight side separately is more accurate. Footing size and post section must be chosen for the fence height, the soil and the wind.