Decking Calculators

Deck boards, joists, posts, and composite decking calculators.

Deck board quantities depend on board width, the gap between boards (typically 1/8 inch for pressure-treated, 3/16 inch for composite), and the direction boards run relative to the joists. Boards running parallel to joists waste less material; diagonal layouts add 15% waste for angled cuts. Hidden fastener systems require different spacing than face-screwed decks. The calculator accounts for all of these variables and outputs board count, linear footage, joist spacing, and an estimated material cost for both pressure-treated lumber and composite decking.