Fence Post Count
Free Fence Post Count calculator with clear step-by-step results.
About Fence Post Count
A straight run needs one more post than it has bays, and every corner and gate adds posts of its own - gates need a post each side. Concrete volume comes from the hole geometry, reduced slightly because the post itself occupies part of the hole.
Formulas
Line posts
Posts = ceil(fence length / post spacing) + 1
Concrete volume
Volume = pi x (hole diameter / 2)^2 x depth x posts x 0.85
Worked example
With the default values below, Fence Post Count returns Posts required of 18. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Fence lengthminimum 0.1 m
- 30 m
- Post spacing (centre to centre)accepts 0.5–6 m
- 2.4 m
- Corners and direction changesaccepts 0–50
- 2
- Gatesaccepts 0–20
- 1
- Depth of the post holeaccepts 200–1,500 mm
- 600 mm
- Hole diameteraccepts 100–800 mm
- 300 mm
Results
- Posts required
- 18 posts
- Line posts along the run
- 14 posts
- Concrete for the post holes
- 0.649 m3
- Bays between line posts
- 13 bays
Step by step
- 1Values used
- 2Line posts
- 3Concrete volume
- 4Posts required= 18 posts
- 5Line posts along the run= 14 posts
- 6Concrete for the post holes= 0.649 m3
- 7Bays between line posts= 13 bays
Assumptions and limits
- The result is derived only from the 6 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
What spacing should I use?
Around 2.4 m suits standard panel fencing; 1.8-2.0 m is better for close-boarded fencing in exposed positions where wind load is high.
How deep should posts go?
A common rule is one third of the above-ground height, with a minimum of 600 mm. In soft or waterlogged ground, go deeper and widen the hole.