🪵 Fence Calculator
Enter your fence length and post spacing, and get the number of posts, panels or sections, and rails you’ll need.
Posts
14
sections + 1 end
Panels / sections
13
Rails
39
3 per section
Sections = length ÷ spacing (rounded up); posts = sections + 1. Add extra posts for corners and gates. 🔒 In your browser.
How the fence calculator works
The number of sections is the fence length divided by the post spacing (rounded up), and the number of posts is the sections plus one (an extra for the final end). The tool also estimates rails, using two or three per section depending on the fence height. Worked example: a 30 m fence at 2.4 m spacing needs ⌈30 ÷ 2.4⌉ = 13 sections, so 13 + 1 = 14 posts, plus two rails per section (26 rails) for a fence up to about 1.2 m high, or three per section (39 rails) for a taller one. The “plus one” post catches the far end of the run, which the section count alone misses.
A common post spacing is 2.4 m (8 ft) for panel fencing. Corners and gates need extra posts, and gate openings interrupt the run, plan those separately.
Frequently asked questions
How many fence posts do I need?
Divide the fence length by the post spacing and round up to get the number of sections, then add one post for the far end. A 30 m fence at 2.4 m spacing needs 13 sections and 14 posts.
What is the standard fence post spacing?
About 2.4 m (8 ft) for panel fencing, or the width of your panels. Closer spacing is stronger and better in windy or exposed spots.
How many rails per section?
Two rails for fences up to about 1.2 m, and three for taller fences, to keep the boards straight and rigid. The tool uses this rule.
Do corners and gates need extra posts?
Yes, each corner and each side of a gate needs its own post, and gate posts should be heavier. Add these to the estimate for your layout.
How deep should fence posts be set?
Usually about a third of the above-ground height, or at least 600 mm (2 ft), set in concrete for stability, deeper for tall or exposed fences.
How many fence panels do I need?
The number of panels equals the number of sections, the fence length divided by the panel (post-spacing) width, rounded up. A 20 m run with 1.8 m panels needs ⌈20 ÷ 1.8⌉ = 12 panels and 13 posts. Round up, because a part-width gap still needs a full or cut panel.
How much concrete do I need per fence post?
It depends on the post and hole size, but a common rule sets each post about a third of its above-ground height deep, in a hole roughly three times the post’s width. Work out the hole volume (π × radius² × depth for a round hole) and subtract the post to size the concrete, the concrete calculator handles the volume.