Fence Calculator

Work out the panels and posts needed for a fence run.

m
m
Panels needed
Posts needed
Full panels cover
Final panel width
Rails (2 per panel)

Covers one straight run. Add posts for gates and corners, and allow for post thickness in the total length.

Counting panels and posts

Divide the run by the panel width and round up to get the number of panels. Posts then follow a simple rule: a straight run needs one more post than it has panels, because the two ends each need closing off.

panels = ⌈length ÷ panel width⌉ · posts = panels + 1

The last panel rarely fits exactly, so expect to trim it to length. Knowing its width up front tells you how much you will be cutting off and whether to nudge the layout.

Worked example

A 20 m run with 1.83 m panels needs 11 panels and 12 posts. Ten full panels cover 18.3 m, leaving a final 1.7 m panel to cut down to size.

Planning a tidy run

A few minutes of estimating saves a wasted trip and an awkward gap. Set posts before ordering all the panels, since real-world ground and obstacles can shift the spacing, and remember that gates and corners each need their own post.

On-site tips

  • Posts go deep. Roughly a quarter to a third of the visible height, set firmly.
  • Account for thickness. Posts add to the run; measure openings carefully.
  • Trim the last panel. Plan where the cut-down panel will sit for the neatest look.

Frequently asked questions

Why is there one more post than panels?
Each panel sits between two posts, and adjacent panels share a post — so a straight run always needs one extra post to close off the final panel.
Does the panel width include the post?
Use the panel’s own width. Post thickness adds a little to the total run, so if you measured a fixed opening, account for the posts or expect the last panel to be trimmed.
How deep should posts go?
A common guide is about a quarter to a third of the post’s above-ground height in the ground, set in concrete or compacted aggregate. Taller fences and windy sites need more.
What about gates and corners?
Gates and changes of direction need their own posts, so add posts for each. This estimate covers a single straight run of panels.