How many fence posts do I need?
Estimate fence posts from fence length, post spacing, straight or uneven runs, corners, ends, gates, and post-hole planning.
Reviewed - May 19, 2026Short answer
For a straight fence, divide total fence length by post spacing, round up, then add one end post. At 8 ft spacing, a 120 ft straight fence needs ceil(120 / 8) + 1 = 16 posts.
For a fence with corners, multiple runs, or gates, count line posts for each run and add corner, end, and gate posts separately so terminal posts are not missed.
For L-shaped fences, U-shaped fences, and yard enclosures, sketch each straight run so shared corners are counted once and uneven sections are rounded separately.
Fence post count method
- Choose the maximum post spacing allowed by the fence system, local code, wind exposure, and site conditions.
- For one straight run, calculate bays as ceil(fence length / post spacing).
- Straight run posts = bays + 1, because the run needs a post at both ends.
- For uneven runs, calculate bays for each straight section separately before adding shared corners, ends, and gate posts.
- For layout mode, estimate line posts by run, then add corner posts, end posts, and gate posts.
- After the post count is known, estimate post-hole concrete from hole diameter, hole depth, and the bag yield.
Quick examples
These examples use current U.S. default fence post spacing logic. Exact post count can change with corners, gate openings, slope, wind exposure, and local code.
Worked example
120 linear ft across 3 runs, 18 posts, 10 in by 30 in holes.
Starter shopping list
- wood fence materials 120 linear ft
- Posts 18 ea (12 line, 6 terminal)
- Concrete 54 bags
- Gate hardware 1 gate set
This example is generated from the same calculator logic used on the Fence cost calculator page.
Straight fence runs
- Measure the fence line itself, not the yard width, and keep the measurement along the planned property line or layout string.
- Round the bay count up before adding the final post, because a partial bay still needs another post.
Corners and gates
- Every turn, end, and gate opening can need a terminal post that is stronger or counted separately from ordinary line posts.
- Gate posts are not the same thing as gate leaves; a single gate opening often uses two gate posts.
Unequal runs and enclosures
- For an L-shape, U-shape, or enclosed yard, sketch each straight section, round bays on that section, then add shared corner posts only once.
- Layout mode uses total length and run count as an early planning shortcut, so use the higher section-by-section count when one side is much shorter or longer than the others.
When to switch modes
- Use quick length mode for one mostly straight fence when you only need an early post count.
- Use layout mode when you know the number of runs, corners, ends, and gate posts. Use post-hole mode when posts are already staked and you mainly need concrete.
Common mistakes
- Dividing length by spacing and forgetting to add the end post.
- Using one straight-run estimate for a fence with corners or gate openings.
- Counting gate leaves but not the gate posts that support them.
- Averaging uneven runs and losing posts at short sections, corners, or gate openings.
- Stretching post spacing beyond the panel, code, soil, or wind limit just to reduce the post count.
- Estimating concrete from post count without checking hole diameter, depth, frost line, and soil.
FAQ
How do I calculate fence posts for a straight fence?
Divide the total fence length by the selected post spacing, round up to get bays, then add one more post for the far end of the run.
How far apart should fence posts be?
Many early estimates use about 8 ft spacing, but the right spacing depends on the fence material, panel system, height, wind exposure, soil, and local code.
Do gates and corners change the post count?
Yes. Corners, ends, and gate openings often need terminal posts that should be counted separately from ordinary line posts.
How do I count posts for an L-shaped or uneven fence?
Sketch each straight run, calculate bays with ceil(run length / spacing) for each run, then add corner, end, and gate posts once. If layout mode averages similar runs, use the manual section count when sides are very uneven.
Should I count posts before estimating concrete?
Yes. Count posts first, then estimate concrete from the number of post holes, hole diameter, hole depth, and bag yield.
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