Deck board calculator

26 boards of 16'13 joists · 676 screws

Deck area: 192.00 SF
Rows: 26 rows × 1 per row
Boards: 26 × 16' (416 LF)
Joists: 13 at 16" on center
Screws (2 per joist): 676 screws

Boards over joists (dashed)

These sketches are here to help you order material and price the work quickly. They are not engineered or shop drawings — always build from your approved project drawings.

Deck length (board direction)Deck width (joist direction)Board widthGap between boards

Length runs the way the boards run (usually along the house); joists run the width.

Board length

Joist spacing

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No waste is added unless you enter it. Joins between boards must land on a joist; picture framing, diagonals and stairs need more.

Waste %

Show the math▾

Rows
width ÷ (board width + gap), rounded up
12' 0" ÷ ( 5-1/2" + 3/16" ) = 26
Boards per row
length ÷ 16' boards, rounded up
16' 0" ÷ 16' = 1
Boards
rows × boards per row
26 × 1 = 26
Joists
length ÷ 16", rounded up, + 1
16' 0" ÷ 16" + 1 = 13
Screws
rows × joists × 2
26 × 13 × 2 = 676

Where the numbers come from

Screws: Two screws per joist, every boardTrex composite screw instructions: "Always use two screws per joist or stair stringer." Hidden-fastener systems are counted differently (usually one clip per joist crossing) — check your system. Board widths: a 5/4×6 or 2×6 is 5½" actual. Gaps between boards vary by product and temperature; use the one in your decking's install guide.Source

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Deck boards, joists and screws for a rectangular wood or composite deck.