Deck Material Calculator
Plan your deck build: estimate decking boards, linear footage, joists, and screws needed based on your deck dimensions.
Board rows
26rows
Linear footage
416ft
Joists needed
13joists
Screws (approx.)
676screws
Deck area: 192 sq ft. Board rows assume a 1/8 in gap between boards and full-length runs — add extra boards for staggered seams on longer decks.
How the deck material calculator works
Decking is calculated by figuring out how many board rows fit across the width of your deck, then multiplying by the length to get total linear footage. Joists are calculated separately based on your chosen on-center spacing.
Formula: rows = width (in) ÷ (board width + 1/8 in gap), rounded up. Linear feet = rows × length. Joists = length (in) ÷ joist spacing, rounded up, plus one extra joist for the starting edge.
Screw count assumes standard face-screwing with 2 fasteners at every point a board crosses a joist — the most common decking fastening method.
Frequently asked questions
1/8 inch is the standard gap for kiln-dried lumber to allow for expansion; some composite manufacturers recommend a slightly different spacing, so always check your product's install guide.
16 inches on-center is standard for most wood decking. Composite decking often requires tighter 12-inch spacing — check your board manufacturer's span rating before you frame.
The linear footage figure is a raw material estimate. Add 10% for cutting waste and staggered seams, and always round up to the nearest standard board length (8, 10, 12, 16, or 20 ft) when ordering.
This calculator assumes 2 screws at every board-joist crossing, which is standard for face-screwed decking. Hidden fastener systems use clips instead and will need a different count from your fastener manufacturer.