Calculate how many deck boards you need based on your deck's dimensions, board width, gap spacing between boards, and board length.
Google AdSense Banner
This area will contain advertisements after approval.
Google AdSense Banner
This area will contain advertisements after approval.
This calculator adds your gap spacing to the board width to get each board's effective coverage width, then divides the deck's total area by that effective width to find the total linear footage of decking needed, before dividing by your chosen board length to get a board count: Boards Needed = (Deck Area ÷ Effective Board Width × (1 + Waste%)) ÷ Board Length.
This calculator covers decking boards (the visible surface) only, it doesn't estimate the substructure beneath (joists, beams, footings) or fasteners, which depend heavily on your specific framing plan, span requirements and local building code, best worked out with a framing plan or contractor.
For a 16 ft × 12 ft deck (192 sq ft) using 5.5 in wide boards with a 0.25 in gap, 12 ft board length, and 10% waste: each board's effective coverage width is (5.5 + 0.25) ÷ 12 ≈ 0.4792 ft. Total linear feet needed = (192 ÷ 0.4792) × 1.10 ≈ 440.8 linear feet. Dividing by the 12 ft board length: 440.8 ÷ 12 ≈ 36.7, rounded up to 37 boards.
Forgetting this calculates decking boards only, the substructure (joists, beams, footings) and fasteners aren't included, and depend on your specific framing plan, span requirements and local building code.
Entering board width in feet instead of inches, this calculator's board width and gap fields expect inches, entering the wrong unit would substantially distort the effective coverage width and resulting board count.
Not accounting for stairs, railings or landings, this covers the main deck surface only, any additional decking on stairs or landings needs to be estimated and added separately.
A small gap is standard between deck boards for drainage and to allow for material expansion, and it slightly increases the effective width each board covers, meaning slightly fewer boards are needed than if boards were laid perfectly edge to edge.
This calculator doesn't assume a specific board orientation, it calculates total linear footage needed based on area and effective coverage width, which works the same regardless of which direction boards run.
No, this covers the main deck surface area only. Stairs, railings and any additional decking on landings would need to be estimated separately and added to this result.
Google AdSense Banner
This area will contain advertisements after approval.