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Fence calculator: panels, posts and post mix
Estimate the panels, posts, optional gravel boards and Tarmac Postmix bags for straight fence runs. Enter each straight section separately, lengths exclude gate openings.
Your result
Your plan starts
with a few details.
Enter your straight fence runs and options, then calculate to see a material list.
For general information only, not professional advice. Rules and prices change, so check the official sources below. Use your own judgement and speak to a qualified builder or engineer before you act.
How the estimate works
For each straight run, the calculator rounds the run length up to whole 1.83 m panel widths, then adds one standard fence support post per run end. Enter corners and slope transitions separately to add support positions. Each gate adds two dedicated gate posts. The gate opening itself is not subtracted from your run length, so measure the fence-only sections on either side.
Post-mix bags are estimated only as standard support positions multiplied by the bags-per-post allowance you enter. The calculator does not use hole dimensions, post dimensions or product yield, and it excludes gate-hole concrete. Adjust the allowance for your actual hole and product before buying.
The UK panel dimensions are one example close-board product, not a universal panel standard. Choose timber or concrete posts to suit the panel system you plan to buy. Optional gravel boards are estimated one per panel, the cited concrete and timber examples have different heights, so check matching products before ordering.
Formula
Count panels and run posts
Panels = ceil(fence-only length ÷ 1.83 m) Run posts = panels + 1 per straight run + extra corner or slope positionsMeasure fence sections without the gate opening. The panel width is the cited UK product example.
Add gate posts and post mix
Gate posts = 2 × number of gates Postmix bags = standard run posts × manual bags-per-post allowanceThe hole dimensions are not used. Gate-post concrete is left out because the source does not give a gate-hole allowance.
Height and planning check
The height checker adds the selected gravel-board height to the panel height. Planning Portal guidance for England says planning permission is generally not needed for a fence up to 1 m beside a highway used by vehicles (including its footpath), or up to 2 m elsewhere. Exceptions can apply, including listed buildings, planning conditions and Article 4 directions. This is an initial England-only check, not a legal decision, rules differ in Wales, Scotland and Northern Ireland. Measure from the relevant ground level and check with your local planning authority.
Worked example
Round up the panels
ceil(10.00 m ÷ 1.83 m) = 6 panelsThe 10 m measurement is for the fence run only, the gate opening is excluded.
Count the posts
6 panels + 1 = 7 run posts 2 × 1 gate = 2 gate postsNo extra corner or slope-transition positions are entered in this example.
Estimate post mix
7 standard posts × 1 bag = 7 × 20 kg bagsThe one-bag allowance is the maker’s estimate for a standard post. Gate-post concrete is not included.
Before you buy
Panel counts are nominal whole-panel estimates. A final bay may need trimming or a different layout. Post spacing, wind exposure, ground levels, gate loads and the fence maker’s installation instructions can change the materials needed. Confirm all measurements and check the sources below.
Frequently asked questions
Do I subtract the gate width from my run?
No. Enter each straight fence-only section and leave the gate opening out of those lengths. The calculator adds two gate posts per gate, but does not estimate gate-post concrete.
Does the planning check apply throughout the UK?
No. The cited Planning Portal guidance is for England. Check the relevant local planning authority and rules in Wales, Scotland or Northern Ireland.
Are the panel and gravel-board sizes universal?
No. They are sourced examples. Confirm that the panels, posts and optional boards are compatible within the system you choose.
Why should I measure each straight fence run separately?
Panel counts round up separately for each entered run. Combining lengths across corners can hide partial panels. Enter fence-only lengths, then record gates, corners and slope steps separately.
Sources
- Standard close-board fence panel specificationsChecked on
- Naylor weather-proof fencing solutions: gravel-board sizesChecked on
- Jacksons timber gravel board specificationChecked on
- Tarmac Postmix technical data sheetChecked on
- Planning Portal: fences, gates and garden walls (England guidance)Checked on
Specs as of: