How to Use the Fence Calculator
Complete the fields in the calculator, then generate a material estimate.
- Enter values in Total fence length, Post spacing (on-center), Panel width (stock size), Rails per panel, Waste / overage %, Number of gates, and Gate width (each), then choose the available units.
- Click Calculate to generate the estimate.
- Use Copy result or Download result (.txt) to save the text output.
- Click Reset to restore the displayed defaults and hide the result.
What the Calculator Estimates
The calculator estimates panels, line posts, gate posts, rails, and total fence run. It subtracts gate openings from the fence run, applies panel waste, uses your post spacing for line posts, and adds two gate posts for each gate.
Fence length accepts feet, inches, yards, meters, or centimeters. Post spacing, panel width, and gate width accept feet or meters.
Formula and Assumptions
The result includes one formula block and a table of intermediate values and assumptions:
Panel run = Fence length - (Gates x Gate width)Panels needed = ceil(Panel run / Panel width x (1 + Waste % / 100))Line posts = ceil(Panel run / Post spacing) + 1Total posts = Line posts + (Gates x 2)andTotal rails = Panels needed x Rails per panel
It assumes one straight fence run. Panel and post counts round up, and Waste / overage % affects panels rather than adding separate waste to posts or rails. Gates use one width for every opening and two dedicated posts per gate. Gate width (each) is checked when gates are entered; a non-empty value in that field is also checked if it remains filled when Number of gates is 0.
Understanding the Result
The result shows headline quantities for panels, posts, rails, and total fence run, followed by intermediate values such as converted dimensions, gate openings, panel run, and the line-post and gate-post breakdown. Use Copy result for the plain-text summary or Download result (.txt) to save it as a .txt file.
This is an estimate based on your entries, not purchasing advice or supplier-specific information.
Limitations and Privacy Scope
The calculator does not provide pricing, supplier availability, purchasing advice, building-code or wind-load lookups, footing requirements, or manufacturer specifications. It does not model corners, curves, slopes, different gate widths, double gates, or footing size and depth.
The calculation uses your entered values in browser-side JavaScript and does not require a calculation request to a server. The page also includes analytics scripts, so this local implementation does not establish a broader claim about whether page data is transmitted.
Frequently Asked Questions
What is the fence panel and post formula?
The calculator subtracts gate openings, applies Waste / overage % to the panel count, rounds panel and line-post calculations up, and adds two posts per gate.
How does the calculator handle gates?
Each gate's width is subtracted from the total fence length before panels and line posts are calculated, since a gate opening replaces a section of fence panel. The calculator then adds 2 dedicated gate posts per gate, since gate hardware typically needs its own posts rather than sharing a standard line post.
Does post spacing come from a building code or wind-load table?
No. Post spacing, panel width, and rails per panel are values you enter yourself. This tool does not look up wind-load ratings, local building codes, or fence-panel specifications - confirm spacing and post depth requirements with your local code and a qualified professional before building.
What units are supported?
Fence length accepts feet, inches, yards, meters, or centimeters. Post spacing, panel width, and gate width accept feet or meters.
Does this tool fetch live pricing or give certified structural advice?
No. It does not fetch material prices, supplier data, or building-code data, and it is not certified engineering, structural, or purchasing advice.