Deck Material Calculator
Plan a rectangular deck using board width, gap, available board length, joist spacing and a material waste allowance.
Deck area240 ft²
Deck-board rows26
Board linear feet572 ft
Boards at selected length36
Approx. joists16
Framing counts are simplified and do not include doubled rims, beams, blocking, stairs, posts, hardware or span-table requirements.
How this tool works
Board rows are deck width divided by board width plus gap. Total decking linear feet are rows × deck length plus waste.
Example
A 20 × 12 ft deck using 5.5-inch boards can be translated into board rows and total linear footage before ordering.
Common questions
Does this design the deck structure?
No. Beam, joist, post and footing sizing must follow span tables, loads, material species and local code.
Why is joist count approximate?
The count assumes regular spacing across one deck dimension and does not include doubled members, rims, blocking or special framing.