Construction & Materials · Verified formula
Fence Calculator
Estimate fence panels, posts, rails and concrete from your fence length and layout.
Formula verified
3+ known-answer test cases
Last verified August 2026
Result
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How to use the Fence Calculator
- Enter your total fence length and the panel width you plan to use.
- Enter the number of gates and corners in the run.
- Confirm rails per panel and concrete bags per post, or use the defaults.
- Select Calculate to see panels, posts, rails and concrete needed.
Formula
Panels and posts
Panels = ceiling(length ÷ panel width) Posts = sections + gate/corner/end adjustments
Assumptions: Baseline post count assumes evenly spaced line posts. Gate posts and corner posts are added on top of the baseline — verify against your specific gate hardware and local frost-depth requirements. This tool provides a general estimate, not professional, engineering, tax or legal advice.
Worked example
Verified example
QA passed
Fence length: 100 ft Panel width: 8 ft Panels = ceil(100 ÷ 8) = 13 Baseline posts = 13 + 1 = 14 Result: 13 panels, 14 baseline posts before gate/corner adjustments
Why this matters: Under-ordering posts or panels stalls a fence build mid-run, and gate or corner posts are easy to forget about until you're standing at the site with a post-hole digger.
Common mistakes
- Forgetting to add dedicated posts for each gate opening — gates need their own posts sized for the hardware, not shared line posts.
- Not accounting for corner posts, which typically need different bracing than straight-run line posts.
- Using panel width when the actual post spacing for your fence style is different from the panel width.
Frequently asked questions
How many fence posts do I need per 100 feet?
At standard 8-foot spacing, a 100-foot run needs about 13-14 posts before adding extra posts for gates and corners.
How much concrete per fence post?
A typical residential post uses one to two 50 lb bags, depending on hole diameter and depth. Deeper posts in high-wind areas need more.
Do gates change the post count?
Yes. Every gate opening needs its own set of posts sized for the gate hardware, in addition to the standard line posts.
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