Garden Fence Length & Cost Calculator

Garden Fencing Guide

What do I need to know about Standard UK Panel Sizes?

Standard UK fence panels: 1.83m wide (6 feet). Heights: 0.9m (3ft), 1.2m (4ft), 1.5m (5ft), 1.8m (6ft). A 1.8m high panel with 2.4m posts gives 600mm in the ground and 1.8m above — the minimum for most garden privacy fences.

What's the key thing to understand about Planning Permission?

UK rules: front garden fences over 1m (next to a road) or side/rear fences over 2m height require planning permission. Always check with your local authority if fencing near a road or boundary. You need your neighbour's agreement to remove shared boundary fencing.

What do I need to know about Installation Tips?

Mark post positions accurately before digging — even one post out of line throws the whole run. Use a string line as a guide. Postcrete sets in minutes, but the post can still be adjusted during the first minute — have a spirit level ready. Let set for 24 hours before hanging panels.

What do I need to know about Fence Height and Wind Loading?

Taller fences catch significantly more wind, which affects both the strength of posts and fixings you need and how exposed a garden feels. A 1.8m (6ft) fence in an open, exposed location experiences considerably more wind load than the same fence in a sheltered garden, which is why fence specifications often differ by exposure rather than height alone. For fences over 1.5m, concrete posts or metal post supports are usually worth the extra cost over basic timber posts, since wind load is the most common cause of fence failure — panels blowing over or posts snapping at ground level. Trellis toppers add height (useful for privacy or climbing plants) without adding as much solid wind resistance as a full panel extension, which is why they're a common choice for exposed boundaries where a taller solid fence would need much stronger foundations. Always check with neighbours and, for fences over 2m, your local authority — planning permission may be required depending on location and height.

What do I need to know about Working Out Which Sides Are Yours to Fence?

Before calculating total fence length, it's worth confirming which boundary or boundaries you're actually responsible for, since gardens are rarely fenced on all sides by the same owner. There's a popular belief that you own 'the fence on your left', but this isn't a legal rule — ownership and maintenance responsibility for a boundary is generally determined by the property's title deeds, which sometimes mark responsibility with a T symbol on the boundary plan, the T pointing into the garden of the owner responsible for that section. Where deeds are silent or unclear, boundaries are often treated as shared by informal agreement between neighbours. This matters for this calculator because the sides-to-fence input should reflect only the boundary length you actually intend to fence, whether through sole or shared responsibility, not the garden's full perimeter — fencing a boundary you don't own or share responsibility for, without agreement, can create a dispute even if done with good intentions. If in doubt, checking the property's title plan before finalising a fencing project avoids this kind of issue.

What should I know about Measuring Length on an Irregular or Sloped Boundary?

Garden boundaries are often not a single straight run — many plots have an angle, a dog-leg, or a boundary that follows a slight slope, and measuring these accurately changes the panel and post count this calculator produces. For a boundary with one or more angles, measure and enter each straight section separately rather than estimating a single straight-line distance between the two end points, since a diagonal shortcut measurement will under-count the materials actually needed. For a sloped boundary, fence panels are typically either stepped, fitted level with a staircase effect down the slope, which keeps panels square but needs careful post height adjustment, or raked, where panels or infill are cut at an angle to follow the ground continuously — stepping is simpler and is what most standard pre-made panels are designed for, while raking usually needs bespoke or trimmed panels and is more commonly handled by a professional fencer. Either approach needs the same total run length for calculating panel count, but stepped fencing on a slope often needs taller posts at the downhill end to maintain a consistent panel height above ground.

How Do You Choose Between Concrete, Spiked, and Postcrete Fence Posts?

Fence post installation method affects both the longevity and the stability of the finished fence, and the right choice depends on soil type, fence height, and how permanent the fence needs to be. Concreting posts into the ground — digging a hole roughly a third of the post's total length deep and filling around it with concrete — provides the most stable, long-lasting fixing and is generally recommended for taller fences (over about 1.5m) or anywhere exposed to significant wind loading, since concrete resists the leverage a tall panel exerts on its posts far better than a shallower fixing. Postcrete (a fast-setting concrete mix poured dry or mixed quickly in the hole) achieves a similar structural result to standard concrete but sets within minutes rather than days, letting the fence be completed the same day rather than waiting for concrete to cure — useful for time-pressured projects, though it's typically a little more expensive per post than standard concrete. Metal spiked post supports, driven or hammered into the ground rather than set in concrete, work well in softer, stone-free soil for lower fences and have the advantage of being removable and reusable, but they're less suitable for heavy clay, stony or very loose/sandy soil, and generally aren't recommended for taller fences or very exposed, windy sites, since they rely on ground friction rather than a solid concrete anchor to resist leverage.

Panel and Post Spacing Reference Table

Different panel widths change how many posts a given length of fence actually needs, which affects both material cost and the total number of concrete footings to dig.

Worked Example: Fence Length for an L-Shaped Garden Boundary An L-shaped boundary made up of a 12m run and an 8m run gives a total fence length of 20m. Using standard 1.8m panels, that's 20 ÷ 1.8 ≈ 11.1, rounded up to 12 panels, requiring 13 posts in total (one extra at the corner where the two runs meet, since the corner post is shared between both directions but still only counts once). At an approximate cost of £35 per panel and £12 per post, materials come to (12 x £35) + (13 x £12) = £420 + £156 = £576, plus roughly £80 of concrete or postcrete for the footings, giving a total materials estimate of around £656 before any gravel boards, caps, or fixings.

Shared Boundary Costs: Splitting Fence Expenses With a Neighbour

Whether a boundary fence's cost should be split with a neighbour depends on legal ownership, not just who happens to want the fence replaced. In England and Wales, there is no automatic legal requirement for neighbours to share fencing costs unless the property deeds specifically say so (sometimes marked with a "T" symbol on a boundary plan, indicating which party owns and must maintain that section) — many people assume a 50/50 split is standard, but it is only standard by common courtesy, not by default law. Before agreeing to split a cost, checking the title deeds or asking a conveyancer to clarify which side of the boundary is "yours" by a T-mark (or by reviewing the original planning permission for the development) avoids a dispute later. Where deeds are silent or ambiguous, many neighbours still choose to split cost roughly down the middle as a practical goodwill measure, particularly for a shared garden boundary with no clear ownership marking — but it's worth getting that agreement in writing (even a simple email confirming the split and who's arranging the work) before any materials are ordered, since verbal agreements over shared costs are a common source of neighbour disputes.

Measuring Length Where a Boundary Includes a Gate

A gate opening needs to be subtracted from the fence-run calculation separately from panel counting, since it occupies linear boundary length but isn't filled with a standard panel. A typical pedestrian gate is around 0.9-1m wide, while a double vehicle gate can be 3-5m wide — either way, measure the gate opening's width first, subtract it from the total boundary length, then calculate panels and posts for the remaining fence-only length, adding two extra posts specifically to carry the gate's hinges and latch (these gate posts are usually sized or reinforced more heavily than standard fence posts, since they bear the gate's weight and the repeated stress of opening and closing).