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.
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 |
This is a quick estimate for a single straight run; add extra posts for corners and gates. It all runs in your browser with nothing uploaded.