Fence Calculator — Posts, Panels, Rails & Concrete

Real-world use cases

• Price a backyard privacy fence before the lumber-yard run

  You're closing in a 30 m back garden with a 1.8 m board fence and want a shopping list, not a guess. Enter 30 m total length, 2.4 m spacing, 2 corners and 1 gate, switch infill to pickets, and set 3 rails per section for the tall privacy run. The tool reads 13 sections, 16 posts (13 + 1 + 2 corners), 12 panels of picket run after the gate, the picket count off your board width and gap, 39 rails and the concrete bags. You walk in with exact quantities and skip the second trip when the last span comes up a post short.

• Lay out a ranch perimeter with long post spacing

  A paddock perimeter is 400 m of three-rail post-and-rail with posts every 3 m to keep the post count (and the digging) down. Enter 400 m, 3 m spacing, set rails to 3, leave infill on panels since post-and-rail is bought per pre-cut rail section. The 134 sections give 135 posts on a closed loop's worth of straight run; add a post for each corner of the paddock. The rail line — sections × 3 — is the number that drives your real lumber order, and the concrete line tells you how many bags to load on the trailer.

• Fence a pool to code without over-buying panels

  Pool barrier codes want a continuous 1.2 m fence with a self-closing gate and no climbable gaps. Enter your pool enclosure perimeter and a 1.8 m spacing for stiffness, set 2 rails (a 1.2 m fence doesn't need three), and enter 1 gate so the calculator deducts that panel — you don't want to buy a panel for the opening the gate fills. The post count keeps your barrier continuous, and the deducted panel stops you over-ordering the one section the gate replaces.

• Estimate temporary site hoarding for a construction job

  A site needs 120 m of 2.4 m temporary hoarding on rented posts at 3 m centres. Enter 120 m and 3 m spacing, infill on panels (the plywood/mesh sheets clip on per bay), 2 rails, and zero concrete bags per post since temporary posts sit in driven sockets or ballast feet, not poured holes. You get 40 sections, 41 posts and 40 sheets to hire — the exact bay count the hoarding supplier prices by, with no concrete cost padding the quote.

• Check a fencing contractor's quote line by line

  A contractor quotes "around 50 posts and 45 panels" for your 100 ft run. Enter 100 ft, 8 ft spacing and your real corner and gate count, and the tool says 13 sections → 14 posts plus corners. If their post number is way over, they may be padding, assuming tighter spacing, or counting gate-post doubling — now you can ask which, instead of nodding at a number you couldn't check. The panel line does the same for the infill: a quote that ignores your two gates is over-counting panels by two.

Common pitfalls

• Buying one post per section. A straight run of N sections needs N+1 posts — the first post plus one to close each span. Buy one-per-section and you finish a post short on the very last span, which means a second trip and a half-set fence waiting on you. This tool adds the +1 (and a post per corner) automatically; just don't subtract it back out by hand.

• Forgetting that spacing is centre-to-centre, not clear gap. Post spacing is the distance between post centres — also the span the panel or rail must cover. Measure the clear opening between installed posts instead and every count drifts, short by one post width. Enter the design spacing your panels are built for (usually 8 ft / 2.4 m), not a tape reading.

• Setting concrete bags from the post count instead of the hole. The bag default here is per hole, not per fence — a light line post might take 1 bag, a 200 mm gate post 3. If you leave it at a flat 2 for a fence that's mostly light line posts, you over-order; if your soil is sandy and you're using bigger holes, 2 may be short. Match the bag number to your actual hole diameter and post duty.

• Ignoring corners and gates. A fence that turns has corner posts that the straight-line count doesn't add, and a gate replaces a panel you'd otherwise buy. Leave both at zero on an L-shaped yard with a gate and you'll be one or two posts short and one panel over. Count the corners off your plan and enter the gates before you trust the totals.

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