Change the board gap before comparing board counts.
In the workshop · Estimate · Browser-local
Deck Material Calculator
Turn dimensions and material choices into a clear deck-material estimate and shopping list.
Deck planning
Build a material estimate before you buy.
Set the deck and material dimensions you intend to use. This browser-local estimate keeps its units and assumptions in view.
Copyable shopping list
What this estimate assumes
Useful buying math, not a structural plan.
Decking runs along the entered deck length. Board rows cover the entered width using board face width plus the installed gap; partial final rows and board runs are rounded up. Joists span the deck width and are counted at the chosen maximum on-center spacing, including one at each end. Fasteners use your per-intersection setting and the same waste allowance. Costs cover only decking boards and joists—not beams, posts, rim boards, blocking, hangers, footings, delivery, tax, or joist length. Confirm framing, spans, attachment, permits, and local code with a qualified professional.
A couple of useful details
Build a clearer lumberyard list.
Enter deck dimensions, board geometry, spacing, waste, and costs. The tool shows each estimate and assumption so you can take a checkable list to the supplier.
No. It is a planning estimate for material quantities and costs, not structural, code, load, or cut-list guidance.