Deck Calculator
Estimate deck boards, joists and screws for any size deck.
ft
ft
in
ft
in OC
Deck boards
35
Joists
13
Screws
280
192 ft² deck
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How the deck calculator works
Board count = (deck length ÷ board length) × (deck width in inches ÷ board actual width). A "5/4×6" board is really 5.5 in wide. Joists at 16 in on-center: (length in inches ÷ 16) + 1.
Frequently asked questions
How many deck boards for a 16×12 deck?
At 12 ft boards and 5.5 in actual width, about 27 boards plus 10% waste — order 30.
How far apart should deck joists be?
16 in on-center for standard decking; 12 in for composite or for spans over 12 ft.
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