Fence Calculator

Divide your total fence length by the post spacing, round up, and add 1: posts = ceil(length ÷ spacing) + 1. For a 100 ft wood privacy fence with 8 ft post spacing, that is ceil(100 ÷ 8) + 1 = 13 + 1 = 14 posts. For an L-shaped yard, calculate each run separately and subtract the shared corner posts: a 60 ft run (9 posts) plus a 40 ft run (6 posts) sharing one corner needs 9 + 6 − 1 = 14 posts. The calculator above does this automatically for up to 4 runs.

Work per post-spacing section: boards per section = ceil(section length in inches ÷ (board width + gap)). For a standard 8 ft section with 5.5 in boards and no gap: ceil(96 ÷ 5.5) = 18 boards. Multiply by the number of sections (total length ÷ spacing). A 100 ft fence gives 18 × 12.5 = 225 boards. For a picket fence with 3.5 in pickets and a 3 in gap: ceil(96 ÷ 6.5) = 15 pickets per 8 ft section, or about 188 for 100 ft. Add 5–10% waste for cuts and defects.

A common rule of thumb is 1 bag of concrete per fence post for a typical residential fence (80 lb bag, roughly 8 in diameter hole, 30 in deep). For larger posts or deeper holes, 2 bags per post is safer. An 80 lb bag yields about 0.6 cubic feet of concrete (60 lb ≈ 0.45, 50 lb ≈ 0.375, 40 lb ≈ 0.30). The calculator defaults to 1 bag per post — adjust it up for corner, gate, and end posts, which take more lateral load.

Material cost per linear foot depends on the fence type. As rough 2026 US estimates: wood privacy $15–$35/ft, picket $12–$30/ft, chain link $8–$18/ft, vinyl $35–$60/ft, and metal/ornamental $40–$75/ft — materials only, before labor. Professional installation roughly doubles these figures. Use the cost estimator in the calculator with your local store prices for an accurate number; it totals every item and shows the per-foot figure.

Measure each straight run separately, then add the runs. Posts: calculate ceil(length ÷ spacing) + 1 for each run and subtract the posts shared at corners (one shared post per connection). Boards, panels, or fabric are based on the combined effective length (total length minus gate widths). The calculator's multi-run mode handles up to 4 runs and does the corner-post subtraction for you — this is the main thing single-run calculators get wrong.

One acre is 43,560 square feet. For a perfectly square acre, each side is √43,560 ≈ 208.7 ft, so the perimeter is about 834.8 ft — roughly 835 linear feet of fence. For 10 square acres the perimeter is about 2,640 ft (half a mile). Real lots are rarely square, so measure your actual boundary or use the farm mode with your acreage as a starting estimate, then verify with a tape or wheel.

A square 10-acre lot has a perimeter of about 2,640 ft. With the standard 4 strands of barbed wire, you need 2,640 × 4 = 10,560 ft of wire. Barbed wire is sold in 1,320 ft rolls (a quarter mile), so ceil(10,560 ÷ 1,320) = 8 rolls. Plan T-posts every 10–12 ft: ceil(2,640 ÷ 12) = 220 posts, plus braced wood corner assemblies. The farm mode computes posts, wire rolls, and corner braces from any acreage.

A practical rule of thumb is 1 joule of energizer output per mile of fence wire (all strands combined). Multiply your perimeter in miles by the number of strands: a 2,640 ft (0.5 mile) fence with 3 strands = 1.5 wire-miles ≈ a 1.5 joule energizer. Add margin for vegetation load — weeds touching the wire drain power. The electric fence mode sizes this for you and also counts insulators (one per strand per post) and ground rods (3 standard).

Typical post spacing: wood privacy and picket fences 8 ft (6–8 ft range); vinyl 8 ft (panel width); metal/ornamental 6 ft (panel width); chain link 10 ft for line posts; barbed wire and farm fence 10–12 ft for T-posts; electric fence 20–30 ft for step-in posts. Wider spacing saves posts but needs stronger rails or wire tension; gate and corner posts should always be heavier (4×6 or 6×6) and set deeper.

A 6 ft privacy fence needs 3 horizontal rails per 8 ft section (top, middle, bottom); fences 4 ft and shorter need only 2. For 100 ft at 8 ft spacing: 3 × 12.5 = 37.5 → 38 rails (2×4 lumber). Picket fences typically use 2 rails per section. The calculator sets rail count from your fence height automatically.

Stockade: boards butted edge to edge on one side (gap 0) — fewest boards. Board on board (board-on-board): boards overlap about 1 in so there are no gaps even as wood shrinks — needs about 22 boards per 8 ft section with 5.5 in boards instead of 18. Shadowbox: boards alternate on both sides of the rails so it looks finished from either side — roughly 1.5× the boards of stockade (about 27 per section). The calculator's privacy style selector adjusts the board count for each.

Posts: ceil(length ÷ 10) + 1 with line posts every 10 ft. Fabric: total length plus 5% waste, divided into 50 ft rolls — for 100 ft: ceil(105 ÷ 50) = 3 rolls. Top rail: one 10 ft stick per 10 ft of fence (10 sticks for 100 ft). Plus 3 ties per post, and a gate frame per gate opening. Corner, end, and gate posts should be larger terminal posts set in concrete. The chain-link mode computes all of this.

Panels = ceil(total fence length ÷ panel width). Vinyl panels are typically 8 ft wide: a 100 ft fence needs ceil(100 ÷ 8) = 13 panels and 14 posts. Metal/ornamental panels are typically 6 ft wide: 100 ft needs ceil(100 ÷ 6) = 17 panels and 18 posts. Subtract gate widths from the length first — gates replace panels. Posts and panels for these fences are a matched system, so buy the brand's own posts.

Subtract the total gate width from your fence length before calculating boards, panels, or fabric — a 100 ft run with one 4 ft gate needs materials for 96 ft. For posts, add 2 heavy-duty gate posts per gate (hinge side and latch side), set deeper in more concrete. The gate planner in the calculator takes the number and width of each gate, adjusts the material length, and adds the gate posts and hardware kits.

Two methods: stepped (panels stay level, stepping down the hill — uses a bit more material and leaves triangular gaps) and racked/racked panels (panels follow the slope — only works on gentle slopes and with rackable panels). For estimates on sloped ground, add extra waste: 5% flat, 10% gentle slope, 15%+ steep slope, because of extra cuts. Chain link and wire fences handle slopes best; pre-assembled vinyl panels handle them worst. The calculator's slope selector sets a sensible default waste percentage.

Cheapest materials: chain link, then wood picket/privacy, then vinyl, then metal/ornamental — but lifetime cost flips the order because wood needs staining and board replacement every few years while vinyl and metal are nearly maintenance-free. Chain link is the cheapest upfront and best for large perimeters (farms, dogs), wood privacy is the best value for privacy, vinyl wins on looks-per-maintenance-dollar, and metal/ornamental wins on security and curb appeal. Compare all five with the same measurements in the calculator to see the real numbers.