Fence Post Spacing Calculator
Estimate fence posts, equal spans, actual post spacing, concrete bags and purchase cost across one or more straight fence runs.
Default project preview
13 posts
Actual spacing
8 ft
Net fence length
96 ft
Spans per run
12
Concrete bags
26
Calculator
Build the material order
Your order will appear here
Enter the project details and calculate a rounded material estimate.
Input and output guide
What each value means
The labels and units below are part of this calculator’s visible methodology. Replace every default with measurements or product data from the actual project.
Total fence length
Enter this project assumption in ft. The current imperial default is 100 ft.
Total gate openings
Enter this project assumption in ft. The current imperial default is 4 ft. Minimum: 0.
Equal straight runs
Enter this project assumption in a unitless value. The current imperial default is 1. Minimum: 1.
Maximum post spacing
Enter this project assumption in ft. The current imperial default is 8 ft.
Concrete bags per post
Enter this project assumption in a unitless value. The current imperial default is 2. Minimum: 0.
Price per post
Enter this project assumption in a unitless value. The current imperial default is 18. Minimum: 0.
Price per concrete bag
Enter this project assumption in a unitless value. The current imperial default is 7. Minimum: 0.
How to read the outputs
Actual spacing
equalized per run. Default preview: 8 ft.
Net fence length
gate openings deducted. Default preview: 96 ft.
Spans per run
96 ft average run. Default preview: 12.
Concrete bags
2 per post. Default preview: 26.
Post cost
posts only. Default preview: $234.00.
Posts and concrete
entered prices. Default preview: $416.00.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Net length = total fence length − gate openings. Spans per run = round up (run length ÷ maximum spacing). Posts = total spans + one terminal post per run.
Reviewed project guidance
How to use this estimate in a real project
Last reviewed: July 29, 2026
Use this calculator to distribute fence posts across a run while keeping actual bay spacing at or below the selected maximum. It is useful for layout and material count, but it does not determine post size, embedment or wind capacity.
Calculation steps
- 1Measure each straight fence run separately.
- 2Subtract gate openings or treat them as separate bays.
- 3Divide by maximum spacing and round the bay count upward.
- 4Add one post to the number of bays.
Worked numerical example
A 100 ft run with an 8 ft maximum spacing requires 13 bays and therefore 14 posts. The actual equal spacing becomes about 7.69 ft.
Purchasing and rounding
Posts are whole units. End, corner, gate and pull posts may require different sizes or hardware and should be identified separately.
Interpret the result
The calculated actual spacing is a layout result. Shorter spacing may be needed for heavy panels, high wind, slopes or product requirements.
Page-specific assumptions
- Straight run with equal bays.
- Posts at both ends.
- Gate and corner conditions handled explicitly.
- Maximum spacing is already appropriate for the system.
Common mistakes
- Rounding the number of bays down.
- Forgetting the final end post.
- Averaging across corners.
- Using panel width as a structural spacing rule without checking the product.
Primary and technical references
BuildMeter provides planning estimates, not engineering, architectural, electrical, mechanical, plumbing, permit or code approval. Review the methodology and verify final decisions with product documentation and qualified professionals.
FAQ
Fence Post Spacing Calculator questions
Why is actual spacing less than the maximum?+
The calculator divides each run into equal spans that do not exceed the entered maximum.
Are gate posts included?+
Gate opening length is deducted, but specialized gate posts and hardware should be added according to the gate design.
Do corner posts need special treatment?+
Often yes. Corners and ends can need stronger posts, bracing or different foundations.