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Fence Materials Calculator

Estimate posts, stringers, palings, a top cap board, and concrete — with board counts and offcuts.

  • fence
  • fencing
  • posts
  • post size
  • 4x4
  • 4x6
  • 6x6
  • 8x8
  • rails
  • stringers
  • palings
  • pickets
  • cap board
  • top rail
  • board lengths
  • cuts
  • offcut
  • corner posts
  • materials
  • canada

About Fence Materials Calculator

A fence is a deceptively simple structure to price: a long run of identical bays, but get the post spacing or paling pitch wrong and the material list is off by enough to mean a second trip to the yard. This calculator takes the run length, post spacing, and paling dimensions and returns the four numbers you actually shop with — how many posts, how many rails, how many palings, and roughly how much concrete the post holes will swallow.

It works the way fences are built: posts divide the run into equal bays, rails span each bay, and palings march across the face at a fixed pitch of board width plus gap. The concrete figure is a planning estimate — fence posts aren't sized in the inputs, so it assumes a typical post in a standard hole and tells you the embedment depth it used so you can sanity-check it against your soil and frost depth.

How to use

Choose metric or imperial, then enter the total fence length and your post spacing — 2.4 m (8 ft) is the common default. Add the fence height (used for the post-hole depth), the width of a single paling, and the gap you want between palings. Set how many rails each bay carries, usually two for a standard fence or three for a tall one.

The results update as you type: post count is always one more than the number of bays, rail pieces are bays × rails, and palings are the run length divided by each board's pitch. The concrete card shows total volume plus the bag count for your unit system. Add an extra post at every corner and gate, and order a handful of spare palings for cuts and the odd warped board.

Pick your post size — 4×4 is standard, with 4×6, 6×6, and 8×8 for taller or heavier fences, or a custom size — and the concrete estimate sizes the hole to suit (about three times the post). Use the stringer presets to set top-and-bottom rails or add a mid-rail, and tick the cap board to add a finishing top rail along the whole run. If your fence ties into an existing fence at a corner, set the shared end posts so those aren't counted or concreted. Finally, enter the stock lengths you'll buy — the tool then tells you how many boards to order for the stringers, cap, and pickets, and whether the lengths cut cleanly or leave offcuts.

Frequently asked questions

  • How many fence posts do I need?

    Divide the total fence length by your post spacing and round up to get the number of bays, then add one — a 24 m run at 2.4 m spacing is 10 bays, so 11 posts. The "plus one" catches the post at the far end of the last bay. Add an extra post at each corner and on both sides of every gate, since those carry more load and aren't part of the straight-run count.

  • What spacing should fence posts be?

    Around 2.4 m (8 ft) is the usual maximum for timber fences and the default here, because standard rail stock comes in lengths that suit it. Closer spacing — 1.8 m (6 ft) — makes a stiffer fence that resists wind better and suits taller or solid-board designs. Wider than 2.4 m and the rails tend to sag between posts. Always keep the spacing even so every bay uses the same rail length.

  • How do I work out the number of palings?

    Each paling occupies its own width plus the gap to the next one — that combined figure is the pitch. Divide the fence length by the pitch and round up. A 90 mm paling with a 10 mm gap has a 100 mm pitch, so a 24 m fence needs 240 palings. Closing the gap to zero (a solid butted fence) raises the count, which is why the gap is a separate input rather than baked in.

  • How much concrete do I need per fence post?

    It depends on the hole size and depth, which depend on the post and your ground. As a planning figure this tool assumes a 100 mm post in a 250 mm-diameter hole embedded the deeper of 600 mm or one third of the fence height, then nets out the post itself. That's typically 20–30 litres of concrete per hole. Treat it as a guide and confirm against local frost-depth requirements before you dig.

  • How deep should fence posts go?

    A common rule is to bury about one third of the post's total length, with a practical minimum around 600 mm, so a 1.8 m-high fence post sits roughly 600 mm in the ground. In colder regions the hole must reach below the frost line — which can be 1.2 m or more across much of Canada — so footings don't heave in winter. Check your local building department, as frost depth varies a lot by province.

  • My fence ties into an existing one — can I skip the corner posts?

    Yes. If one or both ends of the run share a post with an adjacent fence that's already standing, set the "existing shared end posts" option to 1 or 2. The tool drops those posts from the count and from the concrete estimate, since you won't be buying or setting them, but it still builds every bay, rail, and paling between them — the fence sections themselves are unchanged.

  • How do board lengths and cuts affect what I buy?

    Stringers and the cap board run horizontally and are cut to bay lengths, so a stock length that's a whole multiple of your post spacing cuts with no waste — a 4.8 m board makes two clean 2.4 m bay pieces, while a 3.6 m board leaves a 1.2 m offcut each time. Pickets run vertically and are cut to the fence height, so a board cuts cleanly when its length divides by the picket length — an 8 ft board yields two 4 ft pickets with no waste, but only one 6 ft picket plus a 2 ft offcut. Enter your stock lengths and the tool shows the board count, pieces per board, and the offcut for each.

  • Does post size change how much concrete I need?

    Yes, in two ways that partly offset. A bigger post takes up more of the hole, displacing concrete, but it also needs a bigger hole — the rule of thumb is a hole about three times the post's width. The hole growing wins out, so a 6×6 in a 450 mm hole takes noticeably more concrete than a 4×4 in a 300 mm hole. Set the post size (4×4, 4×6, 6×6, 8×8, or custom) and the tool resizes the hole and recomputes the concrete and bag count to match.

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