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Fence Post Quantity Calculator

Work out fence post quantity instantly with clear inputs, formula shown and shareable results.

About Fence Post Quantity Calculator

Post count is the number of spans plus one, because a fence needs a post at both ends of every run, with extra posts added at corners and either side of each gate. A typical 300 mm diameter hole 700 mm deep takes about 50 litres of concrete, so the total is straightforward once the count is known.

Formulas

Post count

Posts = ceil(length / spacing) + 1 + corner posts + 2 per gate

Concrete

m³ = posts x 50 litres / 1000

Worked example

With the default values below, Fence Post Quantity Calculator returns Posts required of 24. Change any input above and every figure here is recalculated in your browser.

Inputs used

Fence lengthminimum 0.1 m
40 m
Post spacingminimum 0.3 m
2.4 m
Corner and end postsminimum 0
4
Number of gatesminimum 0
1

Results

Posts required
24
Fence spans
17
Concrete per post hole
50.0 L
Total concrete required
1.200 m³

Step by step

  1. 1Values used
  2. 2Post count
  3. 3Concrete
  4. 4Posts required= 24
  5. 5Fence spans= 17
  6. 6Concrete per post hole= 50.0 L
  7. 7Total concrete required= 1.200 m³

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is the Fence Post Quantity figure worked out?

Posts = ceil(length / spacing) + 1 + corner posts + 2 per gate. Post count is the number of spans plus one, because a fence needs a post at both ends of every run, with extra posts added at corners and either side of each gate.

Why 2.4 m spacing?

It matches common panel and rail lengths and keeps rails from sagging. Closer spacing is needed for high fences or exposed sites where wind load governs.

What values do I need to enter?

This calculator takes 4 inputs: Fence length, Post spacing, Corner and end posts, Number of gates. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.

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