Construction & trade New Zealand
Fence Calculator NZ
A standard New Zealand timber fence is made of posts set in the ground, rails between them and palings fixed to the rails. This calculator counts the posts, rails and palings from the fence's length and the sizes you choose, and points to the rules that apply to boundary fences.
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Up to 2.5 m is generally exempt from building consent, except pool fences.
Two for up to about 1.5 m high, three for taller fences.
Palings needed
—Fence length less gates
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Posts
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Rails
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Rail length, metres
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Concrete for post holes (approx.)
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The working
A materials estimate. A materials estimate. The structure, post size and embedment depend on height, exposure and soil, so follow the supplier's specification, and check the Fencing Act and Building Act points that apply. Pool fences have their own strict rules and are not covered.
How do I calculate how many palings and posts I need for a fence?
Divide the fence length by the post spacing and add one for the number of posts, and divide the length by the paling width plus the gap for the palings. A 24 m fence with posts every 2.4 m and 100 mm palings with a 5 mm gap needs 11 posts, 20 rails of 2.4 m and about 229 palings.
The Fencing Act
The Fencing Act 1978 sets who pays for a boundary fence between neighbours: the cost is shared equally where one is needed, and a neighbour can serve a fencing notice to start the process. A fence must be a 'sufficient fence', which depends on the use of the land, and the Act allows a neighbour to contribute less in some cases.
Talk to your neighbour before you build, and agree height and design, because the Act's process is slower than a conversation.
Building consent
Under the Building Act 2004, most fences up to 2.5 m high do not need building consent, but pool fences always do, and council rules on height, materials and boundaries may apply. District plans can set rules on fences near roads or in heritage areas.
To work out the concrete for the post holes, use the cubic metre calculator.
How this is calculated
The rule, step by step, so you can check any figure by hand.
posts = (length less gates) ÷ post spacing, rounded up, + 1, + 2 for each gaterails = bays × rails per baypalings = length ÷ (paling width + gap), rounded up, with a wastage allowanceconcrete ≈ posts × hole volume (about 0.03 m³ for a 300 mm hole 450 mm deep)
Spacing sets the cost: closer posts need more concrete and more rails but give a stiffer fence on windy or sloping sites. In exposed parts of New Zealand, posts are often set closer than 2.4 m, and taller fences need heavier posts and deeper holes.
Treated timber must be suited to the use: posts in the ground need a high treatment level (H4 or H5), while rails and palings above ground can use lower classes. Ask your supplier for the right grade for ground contact.
A worked example
A 24 m fence, 1.8 m high, posts every 2.4 m, two rails, 100 mm palings with a 5 mm gap and one 1 m gate.
- Length less the gate23.0 m
- Posts, 23 ÷ 2.4 rounded up + 1 + 213
- Rails, bays × 220
- Palings, 23,000 ÷ 105 with 5% wastage230
About 13 posts, 20 rails and 231 palings.
Gate palings are included in the gate kit and not counted here.
Timber treatment
Posts set in the ground need to be treated to a standard suited to ground contact, usually H4 or H5, and the hole should drain freely. Rails and palings can use a lower class if they are above ground. Ask the supplier which grade suits your site.
What it leaves out
Concrete, fixings, capping, gates, fence gaps for drainage and labour are not included. Uneven ground needs a step plan.
What this calculator does not do
- A materials estimate, not a structural design
- Straight runs; steps and corners change the counts
- Treatment grade must suit ground contact
- Pool fences are separate and strict
Common questions
How far apart should fence posts be in NZ?
Typically 2.4 m apart, closer for taller fences or exposed sites.
Do I need a building consent for a fence?
Most fences up to 2.5 m high are exempt, but pool fences are not. Check with your council.
Who pays for a boundary fence?
Neighbours normally share the cost equally under the Fencing Act 1978.
How many palings do I need?
The fence length divided by the paling width plus the gap, with an allowance for waste.
What timber should I use for posts?
A treatment grade suited to ground contact, usually H4 or H5.
Where these numbers come from
- MBIE — Building Performance New Zealand Building Code and guidance on building work
- New Zealand Legislation — Fencing Act 1978 Who pays for a boundary fence and the fencing notice process
Method last reviewed 2026-10-28 This calculator uses fixed rules rather than rates that change, and its method is re-checked against the sources above at least once a year. Out of date? Tell us and we will fix it.
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