Fence Calculator - Posts, Panels, Rails & Cost

🪵 Fence Material Calculator

Fence Type

Units

Total Fence Length

Fence Height

Post Spacing (centre-to-centre)

Number of Gates

Picket Width

Gap Between Pickets

Number of Rails per Bay

Post Burial Depth

Post Cost Each

Rail Cost per Metre

Picket/Board Cost Each

Concrete per Post (bags)

Fence Length

Fence Sections Planner

Add each side of your property and subtract gate openings.

Side / Section

Length

Gates

Gate Width (each)

Post Spacing

Fence Calculation Guide

Posts, Rails and Pickets

Posts = Floor(Fence Length / Post Spacing) + 1 (Always add 1 for the end post) Gates reduce post count by 1 per gate opening Rails = Posts × Number of Rails per Bay Pickets per Bay = Bay Width / (Picket Width + Gap) Total Pickets = Pickets per Bay × (Posts − 1) Example: 40m fence, 2.4m spacing, 90mm picket, 10mm gap Posts = Floor(40/2.4) + 1 = 17 + 1 = 18 posts Rails = (18−1) × 2 = 34 rails at 2.4m each Bay width = 2.4m = 2400mm Pickets per bay = 2400 / (90+10) = 24 pickets Total pickets = 24 × 17 = 408 pickets

Chain-Link Rolls

Rolls Needed = Ceil(Fence Length / Roll Length) Line Posts = Floor(Fence Length / Spacing) − 1 Terminal Posts = 2 + (2 × number of corners) (Terminal posts at ends, corners and gates are heavier) Total Posts = Line Posts + Terminal Posts Example: 40m fence, 15m rolls, 2.4m spacing Rolls = Ceil(40/15) = 3 rolls Line posts = Floor(40/2.4) − 1 = 15 posts Terminal posts = 2 ends + corners as needed

Concrete for Post Setting

Hole volume = π × (Hole Diameter/2)² × Burial Depth Hole diameter ≈ 3 × Post diameter Burial depth = 1/3 to 1/2 of above-ground height Minimum: 0.6m for most fences For a 1.8m fence: bury at least 0.6m For a 2.4m fence: bury at least 0.75–0.9m Standard rule: 1 bag (50kg) per post for light fences; 2 bags for heavy/tall fences.

Frequently Asked Questions

Divide the total fence length by the post spacing, then add 1 for the final end post (for open runs). Formula: Posts = (Length ÷ Spacing) + 1. For a 40m fence with 2.4m spacing: 40 ÷ 2.4 = 16.67 bays → round up to 17 bays + 1 = 18 posts. For a closed perimeter (all four sides), no '+1' is needed. Add 2 extra posts per gate opening. Standard spacing: wood privacy 1.8–2.4m, chain-link 2.4–3.0m, vinyl panel 2.4m (matches standard panel width).

The standard rule: bury 1/3 to 1/2 of the total post length underground - equivalent to 1/3 to 1/2 of the above-ground fence height. For a 1.8m fence: bury at least 0.6m (total post length 2.4m). For a 2.4m fence: bury at least 0.8–0.9m (total post 3.2–3.3m). Post holes should be roughly 3× the post diameter in width. Always use concrete for permanent fences - one 50kg ready-mix bag per standard post. Allow 24–48 hours before loading the fence.

Pickets per bay = Bay width ÷ (picket width + gap). For a 2.4m bay with 90mm pickets and a 10mm gap: 2400 ÷ 100 = 24 pickets per bay. Multiply by total number of bays. Add 10% for cuts, waste, and future repairs. Common picket widths: 70mm, 90mm, 120mm. Standard gap: 6–12mm. Narrower pickets with tight gaps give more privacy; wider pickets with larger gaps suit decorative styles. The calculator performs this automatically.

Standard spacings: wood privacy fence 1.8–2.4m (use 1.8m for taller or windy sites). Chain-link line posts 2.4–3.0m, with terminal posts always in concrete. Vinyl panel 2.4m (panels manufactured to match). Metal railing 1.8–3.0m depending on height and loading. Closer spacing improves rigidity and wind resistance but increases material and concrete costs. When in doubt, use 2.4m for most residential fences - it's the most common and typically the most cost-effective spacing.

One 50kg bag of ready-mix concrete is sufficient for a standard residential line post (fence 1.2–1.8m high, post hole 400–600mm deep, 200–250mm diameter). For taller fences (above 1.8m), gate posts, and corner posts carrying higher loads, use 2 bags. Fill the hole with concrete to just below ground level after setting the post plumb. In sandy or wet soil, use a full wet-mix pour. In stable clay, dry-pack concrete performs well. Cure for 24–48 hours before loading.

Chain-link is cheapest upfront and works well for large perimeters where appearance isn't critical. Wood is mid-range but requires repainting or staining every 3–5 years - budget approximately 30–40% of initial cost every decade for maintenance. Vinyl/PVC costs 2–3× more than wood initially but requires zero maintenance for 30+ years. Over 20 years, vinyl often costs less in total. Metal/steel is most expensive upfront but lasts 50+ years with periodic painting. For the average homeowner, vinyl is usually the best total cost of ownership.

Measure each straight run separately with a measuring tape and record each section length. For irregular shapes, divide into straight segments. Subtract all gate openings from the total fence length - gates don't need fence panels or pickets, only gate posts. Add up all sections to get total linear footage. For accuracy on large properties, use a measuring wheel, GPS app, or your property survey plan. Add 5% to material orders as a buffer for measurement errors, cuts, and repairs.

In dense rock: drill into rock with a hammer drill and fix posts with chemical anchor bolts - the most secure method. In hard clay or compacted gravel: augering to 600mm is usually achievable and standard concrete-set posts work normally. In very soft or sandy soil: go deeper (700–900mm) and use a larger-diameter hole with more concrete. In areas with tree roots: avoid digging close to large trees and consider surface-mounted post anchors concreted into a pad. Chemical anchors in rock outperform traditional posts in high-wind areas.

Fence Calculator - How to Estimate Posts, Pickets, Rails and Concrete for Any Fence

A fence project that runs short of materials mid-installation is one of the most frustrating and avoidable problems in home construction. Getting the quantities right before you order means no delays waiting for a second delivery, no mismatched material batches, and no overspend on excess stock you can't return. This calculator walks through every material type - posts, pickets, rails, panels, and concrete - for wood, chain-link, vinyl, and metal fences.

Quick example - 40m wood privacy fence, 1.8m high, 2.4m post spacing: Posts needed = 40 ÷ 2.4 + 1 = 18 posts. Rails (3 per bay) = 17 bays × 3 = 51 rails. Pickets at 90mm with 10mm gaps = 24 per bay × 17 = 408 pickets. Concrete = 18 bags (1 per post). Add 10% wastage across all materials.

How to Calculate Fence Posts - The Formula

The post count depends on the total fence length, the post spacing, and whether you're fencing a closed perimeter (where the last post meets the first) or an open run (where you need an end post at each terminus).

For an open run: Number of posts = (Length ÷ Spacing) + 1. The "+1" accounts for the final end post. For a closed perimeter (going around all four sides): Number of posts = Perimeter ÷ Spacing (no "+1" because the last post is the first post).

Always round the bay count up - if your division gives 16.7 bays, that means 17 bays and 18 posts. You can slightly tighten the spacing to keep posts even, but never plan for a fractional bay. Gate posts are in addition to the calculated posts - add 2 per gate opening (one on each side).

Fence Post Depth - The One-Third Rule

The most common mistake in fence installation is setting posts too shallow. The standard rule: the buried depth should be one-third to one-half of the above-ground height. This prevents leaning under wind load and frost heave in colder climates.

1.2m above-ground fence bury at least 0.4–0.6m (total post length: 1.6–1.8m)
1.8m above-ground fence bury at least 0.6–0.9m (total post length: 2.4–2.7m)
2.4m above-ground fence bury at least 0.8–1.2m (total post length: 3.2–3.6m)

Post holes should be approximately 3× the post diameter in width. Fill with concrete for all permanent fences - one 50kg bag of ready-mix concrete per standard residential post, two bags for taller or heavier structural posts. Allow 24–48 hours to cure before attaching rails or panels.

Fence Type Comparison - Cost, Maintenance and Lifespan

Wood & Chain-Link - Budget Options

Chain-link - Lowest upfront cost. Fast to install. Minimal maintenance. No privacy. Best for large perimeters, yards, sports courts.
Wood picket - Classic look, mid-range cost. Requires staining or painting every 3–5 years. Prone to rot and warping if untreated. Lifespan: 15–20 years.
Treated timber - Pressure-treated pine resists rot better. Adds 30–50% to wood cost but doubles lifespan. Common choice for boundary fences in wet climates.

Vinyl & Metal - Premium Options

Vinyl/PVC - 2–3× upfront cost vs wood. Needs no painting, staining, or treatment. UV-stabilised grades last 30+ years. Best long-term total cost of ownership for most residential use.
Aluminium - Lighter than steel, rust-proof, powder-coated. Mid-range cost. Common for pool fencing and ornamental boundaries.
Wrought/tubular steel - Most expensive, most durable. Lasts 50+ years with proper painting. Common for front boundary fences and commercial applications.

Post Spacing - What's Standard for Each Fence Type

Post spacing affects both material cost (more posts = more cost and concrete) and fence strength (closer posts = more rigid). Standard spacings:

Wood privacy fence: 1.8m–2.4m spacing. Shorter spacing for taller fences (1.8m height or more) or high-wind areas.
Chain-link: 2.4m–3.0m between line posts, with terminal posts (corner and end) always in concrete regardless of intermediate spacing.
Vinyl panel: 2.4m is the standard - most vinyl panels are manufactured in 2.4m widths to match this spacing exactly.
Metal railing: 1.8m–3.0m depending on rail height and structural requirement. Pool fencing typically requires closer spacing for compliance.

Gate Planning - What the Calculator Accounts For

Gates require special consideration in any fencing project. Each gate needs two dedicated gate posts - typically heavier gauge or larger diameter than line posts, set deeper in concrete to handle the swinging load. The gate opening width must be measured to the inside faces of the gate posts (not the outside of the posts), as this determines the actual clear opening.

Common gate widths: 900mm–1.2m for pedestrian gates; 2.4m–3.6m for vehicle gates. Double gates can span 3.6m–4.8m. In the perimeter calculator above, entering a gate subtracts the gate width from the total fencing material needed while adding the correct number of gate posts.

How this calculator works, and where the numbers come from

The Fence Calculator applies the standard formula for this calculation to the values you enter and updates the result as you type. The calculation itself happens in your browser, and the page explains the method so you can check any result by hand.

Please note: Results are estimates. Add allowance for waste and check product labels and local building codes before you buy or build.

Sources and further reading

Learn more

Read our guide: How Much Paint, Flooring and Concrete Do You Actually Need?

Last reviewed: October 6, 2026 by the CalcQube Editorial Team. See our editorial policy for how we build and check calculators, or report an error.

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