Fencing · Project planning

Split-Rail Fence Calculator

Use physical rail length and insertion at both post seats to find the effective bay. Count rails, posts and gate openings together.

By Alish Gautam, Software Developer · Updated · Calculation methodology

Start with the editable example below. Dimensions retain their physical size when units change. Region sets currency labels without converting currencies; confirm entered quotes after changing region.

Fence layout

Run length includes gate openings. Gate offset is measured from the run start. Corner and straight connections share the preceding end post.

Run 1
Basic settings
Editable arithmetic example. Replace with your project or product specification.
Product settings
Product and system dimensions
Editable arithmetic example. Replace with your project or product specification.
Editable arithmetic example. Replace with your project or product specification.
Editable arithmetic example. Replace with your project or product specification.
Optional supplier product name, chart revision or quote reference, saved in shared project state.
Advanced settings
Advanced planning settings
Connect the last run back to the first. All runs must form one connected perimeter.
Planning allowance, not a code or industry requirement. Set zero to order the exact rounded takeoff.
Cost settings · USD
Optional quote prices
Optional supplier quote in the selected currency. Blank omits cost.

Project takeoff

Whole packages round up. Allowance is separate from purchased surplus. Prices omit labor, delivery, tax and other items unless explicitly entered.

Total measured fence run
100 ft
Gate openings
0 ft
Net infill length
100 ft
Maximum bay spacing
9.5 ft
Infill bays
11
Physical posts
12
Effective rail bay
9.5 ft
Net requirement
33 rails
Allowance
3.3 rails
Planned requirement
36.3 rails
Unrounded package requirement
36.3
Rails to buy
37
Purchased coverage
37 rails
Surplus beyond planned requirement
0.7 rails

Supplier-ready material list

line posts
10
end posts
2
corner posts
0
gate posts
0
Rails to buy
37
Geometry / layout breakdown
Dimensions use the selected measurement system.
RunInfill (ft)BaysEqual spacing (ft)
Run 1100119.091
Infill span sketch. Shared supports appear in both spans; the physical post total above counts each once. Gate openings are omitted from infill.
Infill span elevationsSpan 1: Run 1 · 11 bays

Use actual rail and mortise dimensions. The estimate assumes the rail system allows the final shortened bay; verify cutting and seating with the supplier.

How it works

Effective bay = rail length − left insertion − right insertion. Sections = ceil(infill span / effective bay); rails = sections × rails per section.

Assumptions and limitations

Use actual rail and mortise dimensions. The estimate assumes the rail system allows the final shortened bay; verify cutting and seating with the supplier.

Whole packages round upward after the chosen allowance. Physical geometry and purchase reserve are separate. Manufacturer and project specifications override editable examples; the selected region does not establish a local code requirement.

Sources and boundaries

This method uses geometric arithmetic and user-entered dimensions. No installation requirement or material property is inferred from a standard.