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Calculator Answers

Fence Calculator

Blake Boege
Written by Blake Boege · Founder, Calculator Answers

A fence calculator is an outdoor construction tool that estimates the materials required to build a boundary fence. Based on the total perimeter length and the desired fence height, the calculator computes the number of fence panels, posts, rails, pickets, and bags of concrete needed for the project. It factors in post spacing intervals (typically six or eight feet) and picket dimensions to create a comprehensive materials list, assisting homeowners, landscapers, and contractors in budgeting and ordering supplies.

Enter the fence length, post spacing, height, gate count, and the fence type. The calculator returns the number of posts, sections, panels or pickets, rails, and an optional concrete bag estimate.

Quick Answer

Estimate the materials needed to build your fence. Enter the total fence length, post spacing, and picket width to generate a detailed supply list.

Fence type

ft

Total run of fence to build. · e.g. 100

ft

Center to center between posts. · e.g. 8

ft

Affects panel and picket lengths, not section counts. · e.g. 6

3 rails common on taller or heavier panel fences. · e.g. 2

Each gate opens the fence run and adds gate posts. · e.g. 1

ft

e.g. 4

ft

Most prefab panels are 6 or 8 ft wide. · e.g. 8

bags

Most 60 lb fast-setting bags use 2 per post. · e.g. 2

Corners, gates, slopes, and property lines often add posts and adjust section layout. Check local code requirements before building.

Fence estimate

96 ft of fence in 12 sections

14 posts

12 panels, 24 rails

Effective length96 ft
Gate opening (total)-4 ft
Sections12
Posts (includes gate posts)14
Panels12
Rails24
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Examples

100 ft panel fence, 8 ft spacing, 1 gate at 4 ft

12 sections, 14 posts, 12 panels, 24 rails

60 ft picket fence, 8 ft spacing, no gates, 5.5 in picket, 0.25 in gap

8 sections, 9 posts, ≈ 126 pickets, 16 rails

200 ft privacy fence, 6 ft spacing, 2 gates at 4 ft each

32 sections, 35 posts (3 with gates), 64 rails

How it works

Subtract the total gate openings from the fence length to get the effective length. Divide that by post spacing and round up for the section count. Posts equal sections plus one, plus one more for each gate. Panels are effective length divided by panel width; pickets are effective length in inches divided by picket width plus gap. Rails are sections times rails per section.

Sections · ⌈(length − gates) ÷ post spacing⌉

Posts · sections + 1 + gates

Panels · ⌈effective length ÷ panel width⌉

Pickets · ⌈(effective length × 12) ÷ (picket width + gap)⌉

Defaults: panel = 8 ft · picket = 5.5 in · gap = 0.25 in · rails per section = 2. Concrete per post is optional.

Planning estimate, not a construction spec. Fence layouts vary by corners, gates, slope, property lines, and local code (height limits, setback rules, permit requirements). Verify property lines and check local codes before building.

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Frequently asked questions

Divide the effective fence length (total length minus any gate openings) by post spacing and round up to get the number of sections. Posts equal sections plus one for the start of the run, plus an extra post for each gate opening (each gate needs its own post at each side). Corners, slope changes, and irregular property lines may add more posts in practice.

Six to eight feet is standard for most residential fences. Six-foot spacing is sturdier for tall privacy fences and windy sites. Eight-foot spacing uses fewer posts and works well with 8 ft prefab panels. Local code may set a maximum.

Two rails (one near the top, one near the bottom) is the common minimum for a 4 to 6 ft fence. Use three rails for taller fences (over 6 ft) or for heavier panels. The calculator multiplies rails per section by the section count to estimate the rail order.

Panel mode uses a prefab panel width (commonly 6 or 8 ft) and counts how many panels span the run. Picket mode uses a picket width plus a gap to count individual pickets. Choose panel for a fast prefab install and picket for a built-on-site board fence with custom spacing.

A common rule of thumb is two 60 lb bags of fast-setting concrete per post hole for a 6 ft wood fence on standard 4×4 posts. Heavier fences, taller fences, sandy soil, or corner posts may need three or more bags per hole. Enter your bag count per post in the optional concrete field and the calculator multiplies it by total posts.

Yes, partially. Gate count and gate width subtract from the effective fence length, which lowers the section count, and each gate adds an extra post to the post total to support the gate hardware. The calculator does not estimate gate hardware (hinges, latch, drop rod) or specialized gate posts. Order those separately.