How many fence panels and posts do I need?

Lay out a straight fence run as equal bays, posts, panels, and rails without assuming a concrete quantity.

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How it works

Run length divided by the maximum installed bay width rounds up to a whole bay count. A straight run adds one terminal post, rails multiply by bays, and run length divided by bays shows the equal centres needed to fit the measured line.

Formula
posts on one straight run = bays + 1
  • Jacksons instructs installers to mark the exact line and lay posts at the centres required by its between-post panels.
  • Panel width and rails per bay are required because closeboard and preassembled panel systems do not share one construction.

Worked example

A 10m run of standard panels
1.83m wide panels, two arris rails per bay
Input
											Run length m: 10
Panel width m: 1.83
Rails per panel: 2
Output
												Bays: 6
Posts: 7
Panels: 6
Rails: 12
Post spacing m: 1.67

When to use this

Preassembled garden panels sit between measured posts, closeboard runs multiply rails per bay, and replacement fences compare old centres with the new system before holes are dug.

Edge cases

  • A 10 m line with a 1.83 m maximum bay needs 6 bays and 7 posts; five bays would exceed the selected spacing.
  • If the run is not divisible by stock panel width, equal centres become shorter and the final design needs trimmed panels or a custom end bay.
  • Corners, gates, and direction changes are absent from one straight run, so their terminal or gate posts must be added in a separate layout.

References