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Decking Calculator

The decking calculator helps you estimate the cost of building a deck by calculating the price of boards and fasteners needed.

Leave at zero to use the dimensions above.
Extra to cover offcuts, breakage and mistakes.
Leave at zero to skip the costing.
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Boards needed3733.39 to cover it, plus 10% waste
Linear length444 ft135.331 m of board in total
Each board covers5.75 sq ft5.75 in effective width × 12 ft
Area to cover192 sq ft
Rows of board26across 12 ft
Boards the gap saves you1compared with butting them tight
Board feet203.5figured at 1 in nominal thickness

The method

boards = covered width ÷ board coverage, plus waste

Face width, not nominal width

A “6-inch” deck board is 5½ inches across, and if you leave a ¼-inch drainage gap each board accounts for 5¾ inches of deck. Working from the nominal 6 inches would leave you several boards short over a large deck.

For cladding the same logic applies to the exposure: lapped siding covers less than its width because each course overlaps the one below.