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Project guide

How many fence panels and posts do I need?

Divide the length of the run by the panel width and round up. You need one more post than panels, plus one for each corner or gate.

Updated Based on manufacturer guidance, sources below

The short answer

Panels = fence length / panel width, rounded up. Posts = panels + 1. A 10m run of standard 1.83m (6ft) panels needs 6 panels, 7 posts, 6 gravel boards and 7 bags of Postcrete. Add one post for every corner or gate.

The formula

  • Panels = fence length / panel width (1.83m for 6ft panels), rounded up
  • Posts = panels + 1, plus 1 for each corner or gate
  • Post length = panel height + gravel board + 600mm in the ground
  • Postcrete = 1 bag per 75mm post

Worked example

A straight 10m run of 1.83m wide, 1.8m high panels on 150mm gravel boards:

  • Panels: 10 / 1.83 = 5.5, so 6 panels
  • Posts: 6 + 1 = 7 posts
  • Post length: 1.8 + 0.15 + 0.6 = 2.55m, so buy 2.7m posts
  • Gravel boards: 6. Postcrete: 7 bags. Panel clips: about 24

Work it out for your job

Change the measurements and the quantities update straight away.

Panels
6 x 1.83m
Posts
7 (add 1 per corner or gate)
Post length
2.55m needed, so buy 2.7m posts
Panel clips
24 (about 4 per panel)

Your list

  • 6Fence panels, 1.83m wide
  • 7Fence posts 75 x 75mm (2.7m)
  • 6Gravel boards 150mm x 1.83m
  • 7Postcrete 20kg (1 bag per 75mm post)
Open the fence calculator with these numbers

Opens the fence panel calculator in SmartBuild with your measurements filled in.

Materials checklist

  • Fence panelsLap, closeboard or slatted. Standard width is 1.83m (6ft).
  • Fence postsPressure-treated 75 x 75mm for panels up to 1.8m. Concrete posts are an alternative.
  • Gravel boardsKeep the panels off the soil so they last longer.
  • PostcreteRapid-setting post mix. Blue Circle allows about three-quarters of a bag for a 75mm post in a 200 x 600mm hole.
  • Panel clips or bracketsAbout 4 per panel to fix panels to timber posts.
  • Post capsStop water soaking into the end grain.

You'll also need

  • Spade or post-hole digger
  • Spirit level and string line
  • Drill/driver and exterior screws
  • Saw for trimming the last panel

Step by step

  1. Measure the runMeasure the full length of the fence line and note corners and gates.
  2. Count the panelsDivide the length by the panel width and round up. Trim the last panel if needed.
  3. Count the postsOne more post than panels, plus one per corner or gate.
  4. Choose the post lengthPanel height plus gravel board plus 600mm in the ground.
  5. Set the postsDig 600mm holes, set each post plumb and fill with Postcrete following the instructions on the bag.

Tips from the manufacturers

  • Bury about 600mm of each post. For 1.8m panels on 150mm gravel boards that means 2.7m posts; 2.4m posts suit 1.8m panels without gravel boards, or 1.5m panels with them.
  • Blue Circle allows about three-quarters of a 20kg bag of Postcrete for a 75mm post in a 200 x 600mm hole, so plan on one bag per post.
  • Set out a string line first and work from one end, fixing each panel before you set the next post.
  • Check where your boundary is and talk to your neighbour before you start.

Mistakes to avoid

  • Forgetting the extra post at each end, corner and gate.
  • Buying 2.4m posts for 6ft panels on gravel boards, which leaves too little in the ground.
  • Setting panels straight onto the soil, so the bottom rots.
  • Building higher than 2m (or 1m next to a road) without checking planning rules.

Frequently asked questions

How many fence panels for 10 metres?

With standard 1.83m panels, 10 / 1.83 = 5.5, so 6 panels. You also need 7 posts.

How many posts do I need for 6 fence panels?

Seven for a straight run: one more than the number of panels. Add one for each corner or gate.

How deep should fence posts be?

About 600mm in the ground for a typical garden fence up to about 1.8m, with the post set in Postcrete or concrete.

How many bags of Postcrete per post?

For a 75mm post in a 200 x 600mm hole, Blue Circle allows about three-quarters of a 20kg bag, so one bag per post. A 100mm post in a 300 x 600mm hole needs about 2 bags.

How high can a garden fence be without planning permission?

In England, up to 2m, or 1m next to a road used by vehicles, under permitted development. Check with your council if you are in a conservation area or your home is listed.

Sources

Quantities are estimates for typical jobs, using the coverage figures above. Products vary, so check the data sheet for the product you buy, and talk to a professional for structural, electrical or gas work. SmartBuild is independent and not affiliated with any of the manufacturers listed.

How many feather-edge boards for a closeboard fence?A closeboard fence is built on site from posts, arris rails and overlapping feather-edge boards. The overlap is what most lists get wrong. How much decking do I need?Boards are the easy part. The frame underneath is where most DIY lists go wrong, so this guide follows the Timber Decking & Cladding Association (TDCA) handbook. How much sand and cement do I need for bricks, blocks or slabs?Work out the volume of mortar first, then split it into cement and sand by the mix. Here are the standard UK rates for brickwork, blockwork and laying paving slabs.

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