Free tool
Deck calculator
Decking boards, joists, and screws from deck size.
Inputs
Estimated materials
- Deck boards
- 29 boards (16 ft)
- Deck area
- 192 SF
- Board rows
- 26
- Joists
- 13 × 12 ft
- Deck screws (2 per joist crossing)
- 710
Assumes boards run the deck length with a 3/16" gap. Beams, posts, footings, ledger, and rim joists aren't included — size framing to your local span tables. Estimate — verify before ordering.
Frequently asked
- How many deck boards do I need?
- Divide the deck depth (in inches) by the board width plus the gap to get rows, multiply rows by deck length for linear feet, add 10% waste, and divide by the board length.
- How many screws per deck board?
- Two screws at every joist crossing — roughly 350 screws per 100 SF at 16" joist spacing with 5.5" boards.
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