Formula and input notes
Boards = ceil(ceil[deck width ÷ effective board width] × ceil[deck length ÷ board length] × allowance factor)
| Input | Practical note |
|---|---|
| Board gap | This is the Decking Calculator layout value for board gap; confirm whether the drawing specifies clear or on-center spacing. |
Worked decking example
Decking Calculator example: The 5.5-in board plus 0.25-in gap creates a 0.4792-ft pitch. A 13.5-ft deck needs 29 rows; 2 boards span each row, and 10% allowance produces 64 boards to order.
Interpret the piece or volume result
Round to whole boards and review the row and boards-per-row logic against a scaled layout before placing a final order.
Cuts, defects, and stock-length effects
Breaker boards, picture framing, angled layouts, butt-joint rules, unusable offcuts, board defects, and required end trimming affect count.
Questions specific to this calculation
Why do board width, gap, and stock length all affect the count?
Enter finished deck dimensions, actual board face width, intended gap, and stock length; calculate separately where board direction or stock length changes.