Deck planning tool
Deck Joist Calculator
Enter the deck dimensions and on-center spacing to estimate joist quantity and total joist footage for planning purposes.
Project planning calculator
Decking Material Estimator
Estimate boards, decking linear footage, joists, and fasteners for a rectangular deck. Enter actual board dimensions for a more useful result.
Project dimensions
Use feet for project and board lengths; use inches for widths and spacing.
Material estimate
Rounded up to whole purchasable quantities.
Deck area
192 sq ft
Deck-board rows
26
Decking to purchase
457.6 linear ft
16-ft boards
29
Estimated joists
13
Joist material
156 linear ft
Deck fasteners
About 744
90-count fastener boxes
9
How this result was calculated
- Rows = deck width across the boards divided by actual board width plus gap, rounded up.
- Decking = rows × board run length × 1.1 for waste.
- Board pieces = decking linear feet divided by stock board length, rounded up.
- Joists are placed perpendicular to the deck boards at the selected on-center spacing.
- Fasteners assume two fasteners at every board-to-joist intersection.
Building it yourself?
Shop your material list
Use the estimate above as a starting quantity, then verify dimensions and compatibility on the retailer product page.
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What to check before buying
- Joists run perpendicular to the deck boards in this estimator.
- The tool estimates quantity and footage; it does not choose joist depth, species, grade, span, beam placement, or cantilever.
- Always verify structural design against applicable code, plans, and local requirements.