Deck Calculator

How to Estimate Deck Materials

This calculator estimates the linear footage of deck boards needed for a rectangular deck.

The method

Board Feet = Deck Area × 12 ÷ Board Width

Deck area = width × length (in feet). The ×12 converts feet to inches for board width compatibility.

Step-by-step

1. Enter your deck width in feet.
2. Enter your deck length in feet.
3. Enter the board width in inches (standard 5.5" for 2×6 decking, 3.5" for 2×4).

Worked example

12 ft × 16 ft deck, 5.5" wide boards. Area = 192 sq ft. Board feet = 192 × 12 ÷ 5.5 = 419 linear feet of decking boards.

Don't forget

This calculates deck boards only. You also need: joists (typically 16" on center), beams, posts, concrete footings, ledger board, joist hangers, screws or hidden fasteners, railing posts and balusters, and stain/sealer. Add 10% extra for cuts and waste.