🪚 Decking Calculator
Deck size and boards
Deck length
(boards run along this direction)
Deck width
Deck board width
5.5 in (14 cm) — standard deck board
3.5 in (9 cm) — 2×4 decking
7.25 in (18 cm) — 2×8 decking
Gap between boards
1/8 in (3 mm)
1/4 in (6 mm) — standard
3/8 in (10 mm)
Board length you buy
8 ft
10 ft
12 ft
16 ft
Joist spacing
12 in on center — extra stiff
16 in on center — standard
24 in on center — light-duty / composite rated
Waste allowance (%)
(extra for cuts, spills and uneven ground — 10% is the usual rule)
Calculate decking
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