Deck Material Calculator

Plan basic deck materials from deck length, width, height, board size, joist spacing, post spacing, railing choice, and decking pattern. The calculator reports decking boards first, then framing pieces, support posts, screws, and optional railing parts.

How to use this calculator

Enter the deck length, width, and height in feet. Choose the deck board size, board length, joist spacing, post spacing, and whether the deck needs railing or diagonal boards. The result updates the board count and supporting material list.

How it works

Deck area is multiplied by boards per foot, based on actual board width:

$boards = ceiling(area \times (12 \div board\ width) \times waste\ factor)$

For a 16 ft by 12 ft deck with 5.5 inch wide boards and a straight pattern, area is 192 sq ft. Boards per foot is about 2.18, and the 10 percent waste factor gives about 461 decking boards by this estimator.

Planning notes

The formula is useful for a rough takeoff, not a cut list. Confirm spans, joist direction, beam sizing, post footings, fasteners, railing code, and board lengths before buying. For footings or pads, compare quantities with the concrete calculator, and use the stud spacing calculator for other framing layouts.