Fence Panel Calculator
Work out how many fence panels, posts, gravel boards, concrete bags and fixings you need for a straight garden fence run.
Measure The Fence Run
Your Material List
Enter the fence run and panel width to build the material list.
How To Measure For Fence Panels
1Mark The Ends
Mark the start and finish points of the fence run. If the fence turns a corner, measure each straight section separately and add the results only after checking corner posts.
2Subtract Openings
Take out the clear width of gates, shared access gaps and fixed openings. A gate still needs posts and hardware, but it is not counted as a fence panel.
3Check Levels
Sloping gardens may need stepped panels, trimmed gravel boards or more labour. A simple length calculation assumes a straight run with normal ground conditions.
4Round Up Carefully
Panels, posts and boards are bought as whole pieces. The calculator rounds up, then applies the waste allowance so you can plan for trimming and mistakes.
Reading The Fence Result
The main panel count is the number of standard panels needed to cover the measured run after subtracting openings and adding your waste allowance. The post count assumes one post at each end and one post between panels. If your fence has a gate, a corner, a change in height or a return into a wall, you may need extra gate posts, corner posts, wall plates or fixings that are not part of the straight-run formula.
The cost line is a materials estimate only. It includes panels, posts, optional gravel boards and postcrete bags based on the prices you enter. It does not include labour, delivery, removal of the old fence, skip hire, staining, screws, brackets, gate hardware, boundary disputes, tree roots, buried services or planning consent. For a contractor quote, keep this material list and ask the installer to explain any extra items.
Formula And Method
Effective fence length = total run – gate or opening width.
Length with waste = effective fence length x (1 + waste percentage).
Panel count = length with waste / panel width, rounded up.
Post count = panel count + 1 for a straight run.
Gravel board count = panel count when gravel boards are included.
Postcrete bags = post count x bags per post, rounded up.
Material estimate = panel cost + post cost + gravel board cost + postcrete cost.
Worked Fence Examples
Small Patio Boundary
A 7.2 m boundary with 1.83 m panels and no gate needs 4 panels before waste. With a small allowance, it still rounds to 5 panels if a closing section needs trimming.
Garden Run With Gate
An 18 m run with a 0.9 m gate leaves 17.1 m for panels. At 1.83 m per panel and 5% waste, the calculator rounds up to 10 panels, then adds 11 straight-run posts.
Sloping Boundary
A sloping 24 m boundary may use the same panel count, but stepped levels can need extra boards, longer posts and more labour. Measure height changes before ordering.
Fence Material Planning Table
| Item | Why It Matters | What To Check |
|---|---|---|
| Panels | Main visible fence sections. Standard UK panels are often 6 ft wide. | Width, height, style, treatment, wind exposure and whether any panel must be cut. |
| Posts | Support each panel and set the spacing. | Timber or concrete, length below ground, corner and gate strength. |
| Gravel boards | Lift panels away from wet ground and can improve life span. | Concrete or timber, height, weight and compatibility with posts. |
| Postcrete | Fixes posts in holes and affects stability. | Hole depth, soil condition, drainage and manufacturer’s bag coverage. |
| Fixings | Clips, screws, brackets and caps are often missed. | Panel type, post material and corrosion-resistant fittings. |
Before You Order
Check who owns the boundary, whether the old fence line is correct, and whether there are trees, drains or cables near post holes. If the fence is next to a road, footpath or listed property, height and planning rules may matter. If wind exposure is high, ask about post spacing, panel type and whether hit-and-miss or open slatted panels would be safer than solid panels.
Delivery is another practical issue. Concrete posts and gravel boards are heavy, and many suppliers charge by vehicle drop. If access is narrow, note where the materials can be placed without blocking neighbours or damaging paving. Order a small number of spare fixings because missing clips can stop a job even when the panel count is correct.
FAQ
How many posts do I need for fence panels?
For a straight run, use one more post than the number of panels. Corners, gates, wall starts and changes in direction can need extra posts.
Do I need to include a waste allowance?
Yes for most jobs. Trimming, damaged boards, uneven ground and closing gaps can all require spare material. Five percent is a practical starting point.
Does the calculator cover featheredge boards?
No. It is for panel fencing. Featheredge, post-and-rail and closeboard fences need different board and rail calculations.
Should I use timber or concrete posts?
Timber is lighter and often cheaper. Concrete is heavier, longer-lasting in many settings and can be better where ground moisture is an issue.
Can I ignore a gate width?
No. Subtract the clear opening from panel length, then price the gate separately with posts, hinges, latch and any frame.
Does this include labour?
No. It estimates materials only. Labour depends on access, ground, old fence removal, waste disposal and local rates.
Sources
- Planning Portal. (n.d.). Fences, gates and garden walls. Planning Portal. https://www.planningportal.co.uk/permission/common-projects/fences-gates-and-garden-walls/planning-permission
- Royal Horticultural Society. (n.d.). Garden boundaries and fences. RHS. https://www.rhs.org.uk/
- British Standards Institution. (n.d.). Timber and fencing product standards. BSI. https://www.bsigroup.com/