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Deck Boards Calculator
Estimate how many deck boards and how much linear footage you need for a deck.
Deck length (board direction)
Deck width
Board width
Gap between boards
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How it works
Rows = deck width ÷ (board width + gap); linear feet = rows × deck length, + waste
Each board covers its own width plus the expansion gap. Divide the deck width by that to get rows, multiply by the run length for total linear footage, then add about 10% for cuts and defects.
Worked example
A 16×12 ft deck with 5.5" boards and 1/4" gaps needs about 26 rows, ~458 linear feet.
Frequently asked questions
Why leave a gap?
Boards expand with moisture and need drainage. A 1/8–1/4" gap prevents buckling and pooling.
Does board length matter?
Buy lengths that divide your run cleanly to reduce waste and avoid weak end-to-end joints.
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This calculator is for educational purposes. Double-check important results before acting on them.