How far apart should fence posts be?

In the UK, standard fence panels are 1.83m (6ft) wide, so posts should be spaced exactly 1.83m apart (centre to centre of each post slot). For post-and-rail fencing, posts are typically spaced 2.4m-3m apart. Never exceed 3m between posts as the fence will be weak in strong winds. This fence post spacing calculator handles standard UK panel sizes and custom widths.

How many bags of postcrete per fence post?

For a standard 75mm or 100mm fence post set 600mm deep, you need 1-2 bags of postcrete (20kg each). For 4-inch (100mm) posts in exposed locations, use 2 bags per post. A 20kg bag of postcrete (also called post mix or quick-set concrete) sets a post in about 5-10 minutes — just add water directly into the hole.

How deep should fence posts be?

Fence posts should be buried to a depth of at least 600mm (2 feet). For a 6ft (1.8m) fence, use 8ft (2.4m) posts with 600mm in the ground. For exposed or windy locations, consider going 750mm deep. The general rule is one-third of the total post length should be underground.

Do I need gravel boards?

Gravel boards are highly recommended for fence panel installations. They sit between the ground and the bottom of the fence panel, protecting the panel from ground moisture, rot and soil contact. Standard gravel boards are 150mm (6 inches) high and the same width as the panel (typically 1.83m). They are much cheaper to replace than a full fence panel.

What other garden boundary options are there?

Besides panel fencing, consider a retaining wall for sloped boundaries — see our Retaining Wall Calculator (/landscaping/retaining-wall-calculator) for block, sleeper or gabion quantities. For garden decking next to a fence, use our Decking Calculator (/landscaping/decking-calculator). If you need gravel for the fence line base, try our Gravel Calculator (/landscaping/gravel-calculator).

TradeCalcs

Fence Post Spacing Calculator — Posts, Panels & Postcrete

Calculate fence post quantities, panel numbers and postcrete bags for your fence run. Based on standard UK panel sizes.

Total Fence Run Length

Total length of the fence run

Panel Width

Include gravel boards

Protects fence panels from ground moisture

Include wastage allowance

Adds 5% extra postcrete

Wastage Percentage

5% recommended for postcrete

Price Per Panel (optional)

Price Per Post (optional)

How We Calculate This

Our fence post calculator works by dividing your total fence run length by the panel width to determine the number of panels, then adds one extra for the end post.

The formula

Number of panels = Total length ÷ Panel width (rounded up)

Number of posts = Panels + 1

Postcrete bags = Posts × 2 bags per post

UK standard sizes

Standard panel width: 1.83m (6ft) — most common UK size
Post size: 75mm × 75mm or 100mm × 100mm
Post length: 2.4m (8ft) for 6ft panels (600mm in ground)
Postcrete: 1-2 × 20kg bags per post
Gravel boards: 1.83m × 150mm per panel bay

Note: If your fence run is not an exact multiple of the panel width, you may need to cut the last panel to fit. The calculator rounds up to whole panels. For corners and direction changes, add an extra post at each corner.

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Verify with your supplier.