CalcCommonsHow to use
Choose prebuilt panels or individual pickets. Measure one uninterrupted straight run, excluding gate openings. Set the maximum span for your chosen fence system, then review counts and the assumptions before ordering.
For related tasks, try the Board Foot Calculator.
Formula & how it works
Sections = round up(run length ÷ maximum span). Posts = sections + 1. Even span = run ÷ sections. Pickets per section = round up((span + gap) ÷ (picket width + gap)). Round the total up again after spare allowance.
Worked examples
Example 1
For one open 100 ft run and an 8 ft maximum span, 100 ÷ 8 rounds up to 13 sections. Plan 14 posts and 13 panels. Even section spacing is about 7.692 ft; fixed-width panels may instead use a shorter last section.
Example 2
For a 24 ft run at 8 ft spans, use 3 sections and 4 posts. With 5.5 in pickets and no gap, each 96 in section needs 18 pickets. A 10% allowance on 54 pickets rounds up to 60; 3 rails per section require 9 rail pieces.
Assumptions & practical notes
Only one open straight run is modeled. Gates, corners, closed loops and shared existing posts change the post count. Do not add run totals without reconciling shared posts.
The section span is a planning measure, not a specified center-to-center post layout. Confirm clear opening, post width and bracket dimensions before setting posts.
Picket counts ignore post widths and allow the edge picket to be trimmed. The selected gap is a uniform spacing assumption, not a safety standard. Footings, fasteners, gate hardware, slope and labor are excluded.
See our calculation methodology for unit definitions and testing practices.
Results are estimates for planning purposes. Verify measurements, product specifications, and applicable building codes before purchasing materials or starting work.
References & measurement guidance
Use the instructions for your selected product and the requirements that apply to your project. Example inputs are not universal specifications.
Frequently asked questions
Why is there one more post than section?
An open straight line needs a post at both ends. Three fence sections therefore need four posts.
How should I handle gates?
Calculate each fence run on either side of a gate separately. Reconcile any shared posts, then add the gate and hardware specified by the manufacturer.
Does the last panel need cutting?
Possibly. Either use equal adjusted sections or full-width panels and a shorter final one, according to the fence system. The estimate rounds purchases up.
Can I use the picket count for a shadowbox fence?
No. The picket model is one flat row. Overlapping, double-sided and shadowbox layouts need a layout-specific count.
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