Fence Calculator
Calculate fence posts, panels, concrete and gate allowances.
About Fence Calculator
A fence always needs one more post than it has bays, and each gate adds a further post because gates hang between dedicated posts. Embedment at a third of the exposed height is the standard rule for wind resistance. Post count and concrete volume are where fence estimates go wrong, and the one-extra-post rule is the most commonly missed part.
Formula
Fence
Posts = bays + 1, plus one extra per gate; embedment is one third of fence height
- bay
- The span between two adjacent posts
- embedment
- Depth of post below ground, conventionally a third of the height above
Worked example
With the default values below, Fence Calculator returns Posts Required of 27. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Fence lengthminimum 0 m
- 45 m
- Post spacingminimum 0.5 m
- 1.8 m
- Fence heightminimum 0.3 m
- 1.8 m
- Number of gatesminimum 0
- 1
- Post hole diameterminimum 100 mm
- 300 mm
Results
- Posts Required
- 27
- Panels Required
- 24
- Concrete Volume
- 0.9733 m3
- Concrete Bags at 25 kg
- 86
- Post Length Needed
- 2.40 m
Step by step
- 1Values used
- 2Fence
- 3Posts Required= 27
- 4Panels Required= 24
- 5Concrete Volume= 0.9733 m3
- 6Concrete Bags at 25 kg= 86
- 7Post Length Needed= 2.40 m
Assumptions and limits
- The result is derived only from the 5 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 4 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 Fence calculated?
Posts = bays + 1, plus one extra per gate; embedment is one third of fence height A fence always needs one more post than it has bays, and each gate adds a further post because gates hang between dedicated posts. Embedment at a third of the exposed height is the standard rule for wind resistance.
Why does Fence matter?
Post count and concrete volume are where fence estimates go wrong, and the one-extra-post rule is the most commonly missed part.
What values do I need to enter?
This calculator takes 5 inputs: Fence length, Post spacing, Fence height, Number of gates, Post hole diameter. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.