Fence Calculator
A straight run divides into spans of the post spacing you type. Posts are spans plus one, then plus extra corners. Rail pieces are spans times rails per span. Estimate only. Gates, slope, and code are not included.
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How to estimate fence posts and rails
- Enter the run length in any length unit you keep consistent. The default is 100.
- Enter post spacing in the same unit. Spacing cannot exceed the run. The default 8 on 100 yields 13 spans.
- Enter extra corners to add posts at turns. A straight run uses 0.
- Enter rails per span. Read spans, posts, rail pieces, and actual spacing. Confirm with a builder. Estimate only.
Fence post and rail takeoff
Straight-run spans plus extra corner posts
| Spans | ceil(length / spacing) |
|---|---|
| Posts | spans + 1 + extra corners |
| Rail pieces | spans × ceil(rails per span) |
| Actual spacing | length / spans |
| Default example | 100 run, 8 spacing, 0 corners, 2 rails |
| Omitted | Gates, slope, frost depth, and code |
What this fence page counts
The run is a single straight length. Spans equal the run divided by spacing, rounded up. Posts sit at both ends, so posts = spans + 1, then extra corners add more posts. Rails are pieces per span, not linear feet of rail stock after cuts. Yard area without a fence line is square footage.
How posts and rails are computed
spans = ceil(length / spacing). posts = spans + 1 + round(corners). rail pieces = spans × ceil(rails). actual spacing = length / spans, which can be slightly tighter than the spacing you typed when the run does not divide evenly. Spacing cannot exceed length. Rails per span must be greater than 0. Corners cannot be negative.
Corners, gates, and code
A corner post is often heavier than a line post. This page only adds a count, not a post class. A gate consumes a span you should subtract from length yourself. Wind, frost, and pool-barrier codes are out of scope. Not structural design.
Use cases
A backyard line of 100 with 8 ft bays, or adding two corners on an L. Not a permit drawing.
Limits
One run. No gate opening. No slope. Estimate only, not code approval. CZNull does not receive the lengths.