How this calculator works
The formula is deck area ÷ covered board width, then × 1.10 for waste. Covered width is the board’s actual face width plus the 1/8-inch drainage gap; the result is converted to linear feet and rounded up to whole boards.
For a 16 ft × 12 ft deck with 5.5-inch boards and 1/8-inch gaps, the covered width is 5.625 inches. 192 sq ft ÷ (5.625 ÷ 12) × 1.10 = about 451 linear feet → 29 boards.
Plan board lengths, seams, and your purchase
Use the board’s actual face width—not the nominal label—and confirm the manufacturer’s required spacing. Choose board lengths from a layout or cut list, then round each length up separately instead of treating the linear-foot result as interchangeable boards. That helps account for butt seams, picture framing, and offcuts. The optional price is your local per-board estimate; it does not include fasteners, framing, delivery, tax, or labor. For non-deck lumber quantities, use the board foot calculator.
Frequently asked questions
What is a standard deck board width?
Most nominal 6-inch decking boards have an actual face width near 5.5 inches; use the product specification for the board you are buying.
How much extra decking should I buy?
This calculator adds 10% for cuts, waste, and the occasional bad board. Complex layouts, diagonal boards, and many seams can require a separate cut-list allowance.