Deck Material Calculator
Estimate decking boards and material cost for your deck
Decking (surface boards) only — framing and footings depend on local building code span tables.
Frequently Asked Questions
Divide your deck's total area by the effective width of one board (the board's face width plus the gap left between boards), which gives the total linear footage of decking needed. Then divide that by the length of board you're buying to get a board count, and add a waste factor for cuts.
1/8 inch (0.125") is the standard gap for pressure-treated lumber to allow for drainage and future expansion. Composite decking often uses a similar or manufacturer-specified gap — check your product's installation guide.
No — this calculator estimates decking (the visible surface boards) and fastener count only. Framing (joist sizing, beams, footing depth) depends on span tables governed by your local building code and the specific lumber species/grade, which this tool doesn't calculate — consult your local code or a contractor for structural framing.
A common rule of thumb is 2 screws per board at each joist crossing — roughly 350 screws per 100 sq ft of decking at 16" joist spacing, or about 467 screws per 100 sq ft at 12" spacing (used for some composite decking). This calculator estimates fastener count from your deck area and joist spacing.
10% is a reasonable default for a simple rectangular deck. Diagonal decking patterns, picture-frame borders, or decks with lots of cuts around posts typically need 15-20%.