How does the post count work?

The run length is divided by the post spacing and rounded up to give the number of panels, then one extra post is added for the end of the run (posts = panels + 1).

What post spacing should I use?

Most timber fence panels are about 1.8m or 2.4m wide, so post spacing usually matches the panel width plus the post itself. Enter the spacing that suits your panels.

How many rails do I need per panel?

Two rails (top and bottom) suit short fences up to about 1.2m; three rails is standard for taller fences around 1.8m to stop boards bowing. Set the rails-per-section field and the tool multiplies it by the number of panels.

Does the calculator handle corners and gates?

No — it estimates a single straight run. For corners, returns or gate openings, calculate each straight section separately and add a post at every corner and on both sides of a gate.

Should I round the result up?

The panel count is already rounded up so the fence reaches the full length, and an extra end post is added automatically. It is still wise to buy a little extra material to allow for cuts and breakages.

Is anything uploaded?

No — the whole calculation runs in your browser and nothing is sent to a server.

What is the Fence Calculator?

Free fence calculator — enter the run length and post spacing to get the number of posts, panels and rails you need. Runs entirely in your browser, nothing is uploaded. It runs free in your browser on Gera Tools, with nothing uploaded.

Fence Calculator — Gera Tools

Name: Fence Calculator
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

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Fence calculator — posts, panels and rails

Planning a new fence run means working out how many posts, panels and rails to buy before a trip to the merchant. This fence calculator turns a run length into a materials list: enter the total length, the spacing between posts, and how many rails each panel uses, and it returns the posts, panels and rails you need for one straight run.

How it works

The tool divides the run length by the post spacing and rounds up to get the number of panels (sections), so the fence always reaches the full length:

panels = ⌈length ÷ spacing⌉
posts = panels + 1 (one extra post closes the end of the run)
rails = panels × rails-per-panel

Works in metres or feet — just keep the length and spacing in the same unit. Most timber panels are 1.8m or 2.4m wide, which is why those are common spacings.

Worked example

For a 30 m run with 2.4 m post spacing and 3 rails per panel:

panels = ⌈30 ÷ 2.4⌉ = ⌈12.5⌉ = 13 panels
posts = 13 + 1 = 14 posts
rails = 13 × 3 = 39 rails

Input	Value
Run length	30 m
Post spacing	2.4 m
Rails per panel	3
Panels	13
Posts	14
Rails total	39

Choosing the right post spacing

Post spacing is usually dictated by the width of the panel or board you are using:

1.8 m (6 ft): standard UK closeboard fence panel width; also common for decorative garden fencing
2.4 m (8 ft): common for larger panel systems; requires a sturdier post in exposed locations
1.2 m (4 ft): for short fences where extra rigidity is needed, or for post-and-rail livestock fencing

If you are using individual featherboard planks rather than pre-made panels, set the spacing at whatever interval gives the right rigidity for the fence height — typically 1.8 m max for a 1.8 m tall fence.

Rails per panel

Rails run horizontally between the posts and hold the vertical boards or planks:

2 rails: suits fences up to about 1.0–1.2 m tall; low garden boundary fencing
3 rails: standard for residential privacy fences 1.5–1.8 m tall
4 rails: for tall security or agricultural fences; also useful in areas with high wind load

Corners, gates and changes of direction

This calculator estimates one straight run. For real-world fencing, add:

One extra post per corner — each change of direction needs its own post, independently of spacing
Two extra posts per gate — one on each side; gate posts are usually larger section than field posts
Posts at end-stop positions — if a run terminates at a wall or structure, add the final closing post

For an L-shaped garden boundary, calculate each straight leg separately, then add posts for the corner.

This is a quick estimate; always buy a small amount of material above the calculated number to allow for cuts, wastage, and any measured adjustments on site. Everything runs in your browser with nothing uploaded.