Free NZ fence calculator for timber paling fences. Posts, rails, palings, fixings and footing concrete from fence length and height, with wastage. No signup.
This calculator counts the posts, rails, palings, fixings and footing concrete in a timber paling fence, from the fence length and height. It is a take-off tool: it counts what a fence of that size needs, it does not design it.
A 12 m paling fence, 1.8 m high, with posts at 1.8 m spacing, 2 rails, 100mm palings and 100 x 100 posts, takes 8 posts, 14 rails and 132 palings. The paling figure includes CostMate's allowance for offcuts.
The posts come out at 2.4 m long, and the post holes take 40 bags of 20kg concrete, 5 to a hole.
Posts are the fence length divided by your post spacing, rounded up, plus one: the closing post at the end of the last bay. Bays are one fewer than the posts, and rails are the bay count times the number of rails you choose, either two or three.
Palings are the fence length in millimetres divided by the paling width, at either 75mm or 100mm, then CostMate's allowance of 10% added.
Heights offered are 1.2m, 1.5m, 1.8m and 2.1m, with post sizes of 100 by 100mm or 125 by 125mm.
The concrete in each hole comes from CostMate's own footing module: the one place that decides how much concrete goes in a hole.
The post standing in the hole is deducted, rather than the hole being counted as though it were empty. A 100 by 100 post through a 600mm embedment displaces about 0.006 cubic metres, which at 0.008 cubic metres to a 20kg bag is about 3 bags saved every 4 holes.
Embedment is not a flat depth either. It slides from about a third toward a half of the fence height, so a 2.1m fence gets a deeper hole than a 1.2m one. The embedment depth is CostMate's allowance.
The page also snaps the required post length up to a stock length, so what it reports is a post you can actually buy rather than a theoretical dimension.
Nails per paling and fixings per rail end are your inputs, not CostMate's assertion. Nailing patterns vary by builder and by job, so you supply the pattern and the geometry does the counting: the same approach the decking calculator takes with screws.
Post embedment, fence height and any retaining function are design decisions. Check them against your plans and your council, and confirm stock lengths with your merchant, before you order or build.