How to calculate your fence project
Fence planning starts with total run length and post spacing. The calculator rounds up to full sections so the layout never exceeds your selected maximum spacing.
- Measure each fence run along the intended line.
- Exclude gate openings or calculate them separately.
- Confirm post spacing, rail count, and picket dimensions for your chosen system.
Formula
The calculation
Fence length ÷ maximum post spacing = sections, rounded up. Posts equal sections plus one for a single run. Pickets are based on total length and picket width.
Worked example
A straight 80 ft fence with 8 ft maximum spacing uses 10 sections and 11 posts. With two rails per section, it needs 20 rails.
The result is a planning estimate. Round purchasing quantities up to available package sizes and confirm the exact product specifications.
Material assumptions
- The default is one straight fence run with 8 ft post spacing.
- Two rails and two 80 lb concrete bags per post are used for planning.
- Gates, corners, slopes, and local frost-depth rules require adjustments.
Read the complete calculator methodology for unit conversions, rounding rules, and limitations.
Why the waste factor matters
A waste or extra-material percentage allows for real-world variation: irregular edges, cuts, compaction, settling, spillage, and measurement error. Ten percent is a useful starting point, not a universal rule. Increase or reduce it according to the material, layout, and supplier guidance.
Unit conversions used
Questions
Fence Calculator FAQ
How far apart should fence posts be?
Eight feet on center is common for many wood fences, but wind, height, material, and local code may require closer spacing.
Does the calculator include gates?
No. Subtract gate openings from the run and add the gate posts and hardware specified by the manufacturer.
How deep should fence posts be?
Depth depends on fence height, soil, wind exposure, frost line, and local code. Verify the design before digging.