Construction

Decking Calculator

Estimate how many deck boards (and linear feet) you need for a deck.

Deck length

Deck width

Board width

Board length

Gap between boards

Waste (%)

Price per board ($)

Calculated Output

Boards needed (boards) 29

Total length 464

Total cost ($) 0

Formula: coverage/board = (boardWidth + gap)/12 × boardLength

Step-by-Step Breakdown

1. Values used:

2. Deck length = 16

3. Deck width = 12

4. Board width = 5.5

5. Board length = 16

6. Gap between boards = 0.125

7. Waste = 10 %

8. Price per board = 0 $

10. Boards needed = 29boards

11. Total length = 464

12. Total cost = 0$

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The math behind it

Each board covers its width plus the gap: (board width + gap) ÷ 12 ft, times its length.

Boards = deck area ÷ coverage per board, rounded up, plus waste.

16×12 ft deck (192 ft²), 5.5 in boards, 1/8 in gap, 16 ft long → coverage 7.5 ft² → 26 boards with 10% waste.

What gap should deck boards have?

1/8 in for pre-dried boards; up to 1/4 in for wet/treated boards that will shrink.