Board on board fence calculator
Calculate pickets for a board-on-board fence, which overlaps boards for full privacy from both sides, with the overlap built into the formula.
Fence calculator
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Overview
Board-on-board overlaps each picket over part of the neighboring board on the opposite side of the rail, so there is no sightline through the fence from any angle, on either side. That overlap means boards are spaced closer together than their own width, which is why this calculator uses a smaller effective picket pitch (board width minus a roughly 1 inch overlap) for this style instead of the plain width-plus-gap formula.
The result is a noticeably higher picket count than a butted privacy fence covering the same run, which matters when comparing quotes between styles.
Common mistakes
- Comparing a board-on-board quote to a privacy-fence quote without accounting for the higher picket count the overlap requires.
- Using the plain width-plus-gap picket formula by hand instead of subtracting the overlap, which understates picket count for this style.
- Assuming the fence is single-sided because it looks solid from one yard; board-on-board is covered from both faces.
Related calculators
- Wood fence calculator Calculate posts, rails, pickets and concrete for a pressure-treated pine, cedar or redwood fence. Every formula shown, cost optional.
- Shadowbox fence calculator Calculate materials for a shadowbox fence, which alternates pickets on both sides of the rails for a semi-private, two-sided look.
- Fence picket calculator Calculate exactly how many pickets you need from your fence run, picket width and gap, including a waste factor.
Related reading
In-depth guides
Frequently asked questions
Why does board-on-board need more pickets than privacy fencing?
Because each board overlaps part of its neighbor rather than butting against it, the effective spacing between board centers is smaller than the board's own width, so more boards fit, and are needed, over the same run.
How much overlap is typical?
Around 1 inch is a common overlap for a 5.5 inch picket, leaving an effective pitch of about 4.5 inches. Deeper overlaps close the fence more on thin boards but raise the count; the amount is a design choice.
Is board-on-board the same as shadowbox?
No. Both look similar from either yard, but board-on-board overlaps boards so the fence is fully closed from every angle, while shadowbox spaces boards with a small gap so light and air pass through.
How much more expensive is board-on-board than privacy?
The price gap is almost all material quantity: the overlap means roughly 20 to 30 percent more boards than a butted privacy fence over the same run, depending on board width and overlap. Posts and rails cost the same.
Does board-on-board provide 100 percent privacy?
Yes, when the overlap is at least a couple of inches and the boards are straight. That full closure from both sides is the practical reason to choose it over shadowbox.
Can I build board-on-board with any species?
Yes, cedar, pressure-treated pine and composite all work. Some composite lines sell an interlocking board-on-board profile at a fixed overlap, in which case use the product's own pitch rather than the default overlap.
Why do contractors charge more per foot for board-on-board?
Two reasons: the higher board count means more material and more handling, and attaching alternating boards takes a bit more labor than butting them flat. Both are real, not markup.
Does the overlap change with board width?
It can. Wider boards can carry a larger overlap while staying structurally fine, but thinner boards lose fixing room. A proportional overlap (around 15 to 20 percent of the width) is a reasonable guide; the 1 inch default is a floor for 5.5 inch boards.