Fence calculator
Estimate fence posts, bays, rails, pickets or panels, and concrete bags from run length and spacing.
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Tool guide
Fence calculator: how it works
Practical information to understand the result and use this tool correctly.
About Fence calculator
This fence calculator turns a straight run into a shopping list: end and line posts, bays, rails on the infill, and either pickets or panels. It is meant for a single straight side of a yard, not a surveyed layout with corners, slopes, or existing walls already counted as posts.
Bays are the run length divided by the center-to-center spacing, rounded up. Posts are bays plus one, so both ends are included. A gate removes its width from the board or panel length and replaces that many bays of rails. If the last bay is shorter than the spacing, it is still counted so you do not under-buy posts.
Pickets use the board width plus the gap as the pitch, then add the waste percent and round up. Panels use panel width the same way. Concrete bags are posts times the bags-per-post figure you enter; leave it at zero if posts are driven or bolted. Optional prices are a material check only, not labor or delivery.
Coverage and spacing should match the product you will buy. A 1.8 m panel fence should use 1.8 m spacing. Privacy boards are often butted (0 mm gap). The tool does not design wind load, post depth, or local setback rules.
How to use it
- 1Enter the straight run in meters and the post spacing center to center.
- 2Set how many gates and each gate width. Gate width is subtracted from the infill.
- 3Choose pickets (board width and gap in mm) or panels (panel width in m), plus rails per infill bay and waste.
- 4Add bags per post and optional unit prices if you want a material total.
- 5Read posts, bays, boards or panels, rails, and bags. Copy the list or reset to a preset.
Frequently asked questions
- How are fence posts calculated?
- Bays equal the run length divided by spacing, rounded up. Posts equal bays plus one so both ends are included. A 12 m run at 2.4 m spacing is 5 bays and 6 posts.
- Do gates add extra posts?
- No. Gate posts are already inside the post count. Each gate removes one bay of rails and its width from the picket or panel length. Do not enter more gates than bays.
- What waste percent should I use?
- About 8–10% covers cut boards and a snapped picket. Use 5% for factory panels that match the bay. Waste does not change the post count.
- Is the layout uploaded?
- No. Lengths and prices stay in the browser and are not sent to a server.
- How is this different from a concrete calculator?
- The concrete tool sizes a slab or columns from a mix ratio. This one counts fence posts and only multiplies bags per post. It does not design footings.