Deck Material Calculator

1/8 inch for kiln-dried lumber, which leaves room to expand. Wet or pressure-treated boards go down tight, because they shrink as they dry and open their own gap. Composites have their own numbers, so check the install guide for yours.

16 inches on center for most wood decking, 12 inches for a lot of composite. Composite is more flexible than wood and sags between joists that are too far apart. Check the manufacturer's span rating before you frame, not after: respacing joists under a finished deck means taking the deck up.

No, the linear footage is raw material. Add 10% for cutting waste and staggered seams, then round up to whatever standard board length you are buying, which is usually 8, 10, 12, 16, or 20 ft. Buying a length that divides evenly into your deck is worth more than the 10%.

Board rows come from the deck width divided by one board's width plus the gap, then multiplied by the deck length for total linear feet. Screws assume 2 at every point a board crosses a joist, which is standard for face-screwed decking. Hidden fastener systems use clips instead, and the count comes from that manufacturer.