Fence Panel & Post Calculator

Fencing Installation Guide

What should I know about Panel and Post Quantities?

For standard 6ft (1.83m) panels: number of panels = fence length ÷ 1.83 (round up). Number of posts = number of panels + 1 (one post at each end, plus one between each panel). Example: 25m fence ÷ 1.83m = 13.66 → 14 panels, 15 posts. Allow for any corners — each corner requires an extra post. Intermediate posts are typically spaced between panels at exactly the panel width — never wider as this causes the panel to flex and fail under wind loading. Gravel boards, the horizontal boards at the base, extend the fence's lifespan significantly by keeping the panels themselves clear of direct ground contact and the damp and rot that comes with it.

What's the key thing to understand about Post Fixing Methods?

Post-mix concrete (Postcrete or similar): dig hole to 600mm deep (or 1/3 of total post length, whichever is greater), place post, pour dry Postcrete mix around post, add water, hold plumb for 3-4 minutes while it sets. 2-3 bags per post (20kg each). Fast, strong, permanent. Metal fence spikes: driven directly into firm ground, post slots into the sleeve. No concrete required — quicker and removable. Only suitable for firm, stone-free ground. Not recommended for tall or exposed fences. Not suitable for fences taller than about 1.5m, since the lack of a concreted-in post reduces overall stability in wind.

What should I know about Post Length Selection?

Total post length = above-ground height + depth in ground. Minimum in-ground depth: 600mm for standard 6ft fence (1/3 of above-ground height is a good rule). For 1.83m above ground: post length = 1.83 + 0.6 = 2.43m — round up to 2.4m (common stock length) and allow 10cm adjustment margin. Longer posts for sloped ground, soft soil, or exposed coastal/hillside sites. UK standard fence post sizes: 75×75mm timber (most common), 100×100mm (heavier panels or taller fences), or steel box sections for larger, more demanding installations where timber alone wouldn't provide sufficient strength.

What should I know about Planning Permission and Party Walls?

In England, you can erect a fence up to 2 metres tall without planning permission on most residential properties (1 metre if adjacent to a highway or public footpath). Conservation areas and listed buildings may have additional restrictions. Party wall / boundary matters: always confirm the boundary line before installing a fence — use the title deeds or commission a boundary survey if uncertain. Fence posts must be on your side of the boundary line. Good practice: discuss with neighbours before starting work, even where no formal permission or notice is legally required, since boundary disputes are a common and often avoidable source of neighbour conflict.