Fence Picket Spacing Calculator

Lay out pickets from the opening you actually have

Fence picket spacing is easy to get wrong when the opening is not an even multiple of the picket width. This calculator starts with the real clear opening, the actual picket width, and the maximum gap you want. It then finds a practical picket count and produces the center mark for every picket.

Maximum gap versus actual gap

The maximum gap is a limit, not a target. MeasureMarks increases the picket count until the calculated clear gap is at or below that limit. The result section shows the actual finished gap and the center-to-center spacing so you can verify the layout before fastening anything.

Before you mark the rail

• Measure between the finished inside faces of the posts or other true boundaries.
• Use the actual picket width; nominal lumber sizes can differ from the installed face width.
• Choose flush ends only when the first and last pickets should touch the boundaries.
• Check local requirements where fence opening size matters for safety or code.