Fencing Calculator
Panels, posts and gravel boards for a fence run.
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About this calculator
Fence runs are built from repeating panel-and-post bays, so the shopping list follows from one measurement: the run length. This calculator works out panels, posts (always one more than panels), gravel boards and the postcrete to set everything solid.
The formula
Panels = Run ÷ Panel width (round up)
Posts = Panels + 1
Postcrete ≈ 2 bags per post
Worked example
A 22m run of 1.83m (6ft) panels: 13 panels, 14 posts, 13 gravel boards, ~28 bags of postcrete.
Common mistakes
- Measuring along sloping ground as if it were flat — step the panels or measure the true run.
- Burying posts too shallow: 60cm in the ground is the norm for a 1.8m fence.
- Forgetting the boundary conversation with your neighbour before the old fence comes down.
Frequently asked questions
Concrete lasts decades and won't rot but is heavier and less attractive; timber looks better and is easier to work with but has a shorter life at ground level.
They sit between the ground and the panel, sacrificially taking the ground moisture so the panel doesn't rot from the bottom.
In most UK gardens, 2m without planning permission (1m next to a highway) — check local rules.
Assumptions & limitations
Straight run with standard 1.83m panels; gates are extra.
Sources & verification
- Manufacturer panel and post dimensions — UK fence panels are commonly 1.83 m (6 ft) wide; confirm dimensions with your supplier
All sources last accessed 24 July 2026.
Formula last verified: 24 July 2026
Maintained by: Steve Davis, Founder & Editor — see our editorial standards
Spotted an error or an out-of-date figure? Report it — corrections are prioritised over all other work (see our corrections policy).
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